NCERT Solutions for Class 7 Maths Chapter 11 Perimeter and Area - Download PDF

NCERT Solutions for Perimeter and area class 7 - If you want to cover the floor of the room. The first question that comes in mind is how many square meters of flooring you need? It can be done by measuring the area of the room. In the practical case, you will buy slightly higher than the required area since there may be cuts and joints required for the flooring. The perimeter can be calculated by adding the length of all sides of the closed figure. In this chapter, you will study the perimeters of some simple geometry like rectangle, triangle, parallelogram, and circles.

You should try to solve all the NCERT problems including examples for a better understanding of the concepts. In CBSE NCERT solution for Class 7 Maths chapter 11 Perimeter and Area, you will get some complex geometry problems which will give you more clarity. You can get NCERT Solutions from Classes 6 to 12 by clicking on the above link. Here you will get solutions to four exercises of this chapter. Students are supposed to refer to the NCERT Class 7 Syllabus and know the exam pattern and important topics.

NCERT Solutions for Maths Chapter 11 Perimeter and Area Class 7 - Important Formulae

Perimeter of a Triangle = Side1 + Side2 + Side3

Perimeter of a Square = 4 × side of square

Perimeter of a Rectangle = 2 × ( Length + Breadth or Width )

Circumference or Perimeter of a Circle = πd = 2πr

Where d = Diameter of circle = 2r, r = Radius of circle

Area of a Square = Side × Side

Area of rectangle = Length × Breadth

Congruent parts of rectangle:

The area of each congruent part = (1/2) × ( The area of the rectangle )

Area of a parallelogram = Base × Height

Area of a Triangle = (1/2) × ( Base) × ( Height)

All the congruent triangles are equal in the area but the triangles equal in the area need not be congruent.

Area of a circle = πr2 where, r = Radius of circle

Unit Conversions:

1 cm2 = 100 mm2

1 m2 = 10000 cm2

1 hectare = 10000 m2

NCERT Solutions for Class 7 Maths Chapter 11 Perimeter and Area - Important Points

Perimeter: The total length of the boundary of a two-dimensional shape.

Circumference: The distance around the boundary of a circle.

Area: The measure of the space enclosed by a two-dimensional shape.

Congruent: Two shapes are congruent if they have the same size and shape.

Base: The bottom side of a two-dimensional shape, like a parallelogram or triangle.

Height: The perpendicular distance between the base and the opposite side in a two-dimensional shape.

Diameter: The longest chord (line segment connecting two points on a circle) passing through the center of a circle.

Radius: The distance from the center of a circle to any point on its boundary.

Unit Conversions: Converting measurements from one unit to another, based on their relationships.

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NCERT Solutions for Maths Chapter 11 Perimeter and Area Class 7

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NCERT Solution for Class 7 Maths Chapter 11 Perimeter and Area (Intext Questions and Exercise)

NCERT Solutions for Maths Chapter 11 Perimeter and Area Class 7 Topic 11.2

Question:1 What would you need to find, area or perimeter, to answer the following?

How much space does a blackboard occupy?

Answer: The space of the board includes the whole area of the board

Question:2 What would you need to find, area or perimeter, to answer the following?

What is the length of a wire required to fence a rectangular flower bed?

Answer: The length of the wire to fence a flower bed is the circumference of the flower bed

Question:3 What would you need to find, area or perimeter, to answer the following?

What distance would you cover by taking two rounds of a triangular park?

Answer: Distance covered by taking round a triangular park is equal to the circumference of the triangular park

Question:4 What would you need to find, area or perimeter, to answer the following?

How much plastic sheet do you need to cover a rectangular swimming pool?

Answer: Plastic sheet need to cover is the area of the rectangular swimming pool

Question:2 Give two examples where the area increases as the perimeter increases.

Answer: A square of side 1m has perimeter 4 m and area 1 m 2 . When all sides are increased by 1m then perimeter =8m and area= 4 m 2 . Similarly, if we increase the length from 6m to 9m and breadth from 3m to 6m of a rectangular the perimeter and area will increase

Question:3 Give two examples where the area does not increase when perimeter increases.

Answer: Area of a rectangle with length = 20cm, breadth = 5 cm is 100cm 2 and perimeter is 50 cm. A rectangle with sides 50 cm and 2 cm ha area = 100cm 2 but perimeter is 104 cm

NCERT Solutions for Maths Chapter 11 Perimeter and Area Class 7 Exercise: 11.1

Question: 1(i) The length and the breadth of a rectangular piece of land are and respectively. Find its area

Answer: It is given that the length and the breadth of a rectangular piece of land are and

Now, we know that

Area of the rectangle (A) =

Therefore, area of rectangular piece of land is

Question: 1(ii) The length and the breadth of a rectangular piece of land are and respectively. Find the cost of the land, if of the land costs

Answer: It is given that the length and the breadth of a rectangular piece of land are and

Now, we know that

Area of the rectangle (A) =

Now, it is given that of the land costs

Therefore, cost of of land is

Question: 2 Find the area of a square park whose perimeter is .

Answer: It is given that the perimeter of the square park is

Now, we know that

The perimeter of a square is (P) , where a is the side of the square





Now,

Area of the square (A)



Therefore, the area of a square park is

Question: 3 Find the breadth of a rectangular plot of land, if its area is and the length is . Also find its perimeter.

Answer: It is given that the area of rectangular land is and the length is

Now, we know that

Area of rectangle is





Now,

The perimeter of the rectangle is



Therefore, the breath and perimeter of the rectangle are 20m and 88m respectively

Question: 4 The perimeter of a rectangular sheet is . If the length is , find its breadth. Also find the area.

Answer: It is given that perimeter of a rectangular sheet is and length is

Now, we know that

The perimeter of the rectangle is









Now,

Area of rectangle is



Therefore, breath and area of the rectangle are 15cm and respectively

Question: 5 The area of a square park is the same as of a rectangular park. If the side of the square park is and the length of the rectangular park is , find the breadth of the rectangular park

Answer: It is given that the area of a square park is the same as of a rectangular park and side of the square park is and the length of the rectangular park is

Now, we know that

Area of square

Area of rectangle

Area of square = Area of rectangle







Therefore, breadth of the rectangle is 40 m

Question: 6 A wire is in the shape of a rectangle. Its length is and breadth is . If the same wire is rebent in the shape of a square, what will be the measure of each side. Also find which shape encloses more area?

Answer: It is given that the length of rectangular wire is and breadth is .

Now, if it reshaped into a square wire

Then,

The perimeter of rectangle = perimeter of the square







Now,

Area of rectangle

Area of square

Therefore, the side of the square is 31 cm and we can clearly see that square-shaped wire encloses more area

Question: 7 The perimeter of a rectangle is . If the breadth of the rectangle is , find its length. Also find the area of the rectangle.

Answer: It is given that the perimeter of a rectangle is and breadth is

Now, we know that

The perimeter of the rectangle is






Now,

Area of rectangle is



Therefore, the length and area of the rectangle are 35cm and respectively

Question: 8 A door of length and breadth is fitted in a wall. The length of the wall is and the breadth is (Fig11.6). Find the cost of white washing the wall, if the rate of white washing the wall is

Answer: It is given that the length of door is and breadth is and the length of the wall is and the breadth is

Now, we know that

Area of rectangle is

Thus, the area of the wall is



And

Area of the door is



Now, Area to be painted = Area of wall - Area of door = 16.2 - 2 = 14.2

Now, the cost of whitewashing the wall, at the rate of is



Therefore, the cost of whitewashing the wall, at the rate of is Rs 284

NCERT Solutions for Class 7 Maths Chapter 11 Perimeter and Area Topic 11.2.2

Question 1: Each of the following rectangles of length 6 cm and breadth 4 cm is composed of congruent polygons. Find the area of each polygon.

Answer:

The total area of rectangle

i) The first rectangle is divided into 6 equal parts. So the area of each part will be one-sixth of the total area

ii) The rectangle is divided into 4 equal parts, area of each part= one-forth area of rectangle= 6 cm 2

iii) and (iv) are divided into two equal parts. Area of each part will be one half the total area of rectangle= 12 cm 2

v) Area of rectangle is divided into 8 equal parts. Area of one part is one-eighth of the total area of rectangle = 3 cm 2

NCERT Solutions for Class 7 Maths Chapter 11 Perimeter and Area Topic 11.3

Question:1(i) Find the area of following parallelograms:

Answer: Area of the parallelogram is the product of base and height

Question: 1(ii) Find the area of following parallelograms:

Answer: Area of the parallelogram is the product of base and height

Question:(iii) Find the area of the following parallelograms:

In a parallelogram , and the perpendicular from on is

Answer: Area of parallelogram = the product of base and height

NCERT Solutions for Class 7 Maths Chapter 11 Perimeter and Area Exercise 11.2

Question: 1(a) Find the area of the following parallelograms:

Answer: We know that

Area of parallelogram

Here,

Base of parallelogram = 7cm

and

Height of parallelogram = 4 cm



Therefore, the area of the parallelogram is

Question: 1(b) Find the area of the following parallelograms:

Answer:

We know that

Area of parallelogram

Here,

Base of parallelogram = 5cm

and

Height of parallelogram = 3 cm



Therefore, the area of the parallelogram is

Question: 1(c) Find the area of the following parallelograms:

Answer: We know that

Area of parallelogram

Here,

Base of parallelogram = 2.5cm

and

Height of parallelogram = 3.5 cm



Therefore, area of parallelogram is

Question: 1(d) Find the area of the following parallelograms:

Answer: We know that

Area of parallelogram

Here,

Base of parallelogram = 5cm

and

Height of parallelogram = 4.8 cm



Therefore, the area of a parallelogram is

Question: 1(e) Find the area of the following parallelograms:

Answer: We know that

Area of parallelogram

Here,

Base of parallelogram = 2 cm

and

Height of parallelogram = 4.4 cm



Therefore, the area of a parallelogram is

Question: 2(a) Find the area of each of the following triangles:

Answer: We know that

Area of triangle

Here,

Base of triangle = 4 cm

and

Height of triangle =3 cm



Therefore, area of triangle is

Question: 2(b) Find the area of the following triangles:

Answer: We know that

Area of triangle

Here,

Base of triangle = 5 cm

and

Height of triangle =3.2 cm



Therefore, the area of the triangle is

Question: 2(c) Find the area of the following triangles:

Answer: We know that

Area of triangle

Here,

Base of triangle = 3 cm

and

Height of triangle =4 cm



Therefore, area of triangle is

Question: 2(d) Find the area of the following triangles:

Answer: We know that

Area of triangle

Here,

Base of triangle = 3 cm

and

Height of triangle =2 cm



Therefore, the area of the triangle is

Question: 3 Find the missing values:

Answer: We know that

Area of parallelogram

a) Here, base and area of parallelogram is given





b) Here height and area of parallelogram is given





c) Here height and area of parallelogram is given





d) Here base and area of parallelogram is given



Question: 4 Find the missing values:

Answer: We know that

Area of triangle

a) Here, the base and area of the triangle is given





b) Here height and area of the triangle is given





c) Here base and area of the triangle is given



Question: 5(a) is a parallelogram (Fig 11.23). is the height from to and is the height from to . If and

Find:

the area of the parallelogram

Answer: We know that

Area of parallelogram

Here,

Base of parallelogram = 12 cm

and

Height of parallelogram = 7.6 cm



Therefore, area of parallelogram is

Question: 5(b) is a parallelogram (Fig 11.23). is the height from to and is the height from to . If and

Find:

, if .

Answer: We know that

Area of parallelogram

Here,

Base of parallelogram = 12 cm

and

Height of parallelogram = 7.6 cm



Now,

The area is also given by





Therefore, value of QN is

Question: 6 and are the heights on sides and respectively, of parallelogram (Fig 11.24). If the area of the parallelogram is and find the length of and

Answer: We know that

Area of parallelogram

Here,

Base of parallelogram(AB) = 35 cm

and

Height of parallelogram(DL) = h cm





Similarly,

Area is also given by





Therefore, the value of BM and DL are is 30cm and 42cm respectively

Question:7 is right angled at (Fig 11.25). is perpendicular to . If and Find the area of

. Also find the length of .

Answer: We know that

Area of triangle

Now,

When base = 5 cm and height = 12 cm

Then, the area is equal to



Now,

When base = 13 cm and height = AD area remain same

Therefore,





Therefore, the value of AD is and the area is equal to

Question: 8 is isosceles with and (Fig 11.26). The height from to is Find the area of

What will be the height from to i.e., ?

Answer: We know that

Area of triangle

Now,

When base(BC) = 9 cm and height(AD) = 6 cm

Then, the area is equal to



Now,

When base(AB) = 7.5 cm and height(CE) = h , area remain same

Therefore,





Therefore, value of CE is 7.2cm and area is equal to

NCERT Solutions for Class 7 Maths Chapter 11 Perimeter and Area Topic 11.5.1

Question:(a) In Fig Which square has a larger perimeter?

Answer: The outer square has a larger perimeter. Since each side of the inner square forms a triangle. The length of the third side of a triangle is less than the sum of the other two lengths.

Question:(b) In Fig 11.31, Which is larger, perimeter of smaller square or the circumference of the circle?

Answer: The arc length of the circle is slightly greater than the side length of the inner square. Therefore circumference of the inner circle is greater than the inner square

NCERT Solutions for Class 7 Maths Chapter 11 Perimeter and Area Exercise 11.3

Question: 1(a) Find the circumference of the circles with the following radius: (Take )

Answer: We know that

Circumference of a circle is



Therefore, the circumference of the circle is 88 cm

Question: 1(b) Find the circumference of the circles with the following radius: (Take )

Answer: We know that

Circumference of circle is



Therefore, the circumference of the circle is 176 mm

Question: 1(c) Find the circumference of the circles with the following radius: (Take )

Answer: We know that

Circumference of circle is



Therefore, circumference of circle is 132 cm

Question: 2(a) Find the area of the following circles, given that:

(Take )

Answer: We know that

Area of circle is



Therefore, the area of the circle is

Question: 2(b) Find the area of the following circles, given that:

Answer: We know that

Area of circle is



Therefore, area of circle is

Question: 2(c) Find the area of the following circles, given that:

Answer: We know that

Area of circle is



Therefore, the area of the circle is

Question: 3 If the circumference of a circular sheet is find its radius. Also, find the area of the sheet. (Take )

Answer: It is given that circumference of a circular sheet is 154 m

We know that

Circumference of circle is







Now,

Area of circle



Therefore, the radius and area of the circle are 24.5 m and respectively

Question: 4 A gardener wants to fence a circular garden of diameter . Find the length of the rope he needs to purchase if he makes rounds of fence. Also find the cost of the rope, if it costs (Take ).

Answer: It is given that diameter of a circular garden is .

We know that

Circumference of circle is



Now, length of the rope requires to makes rounds of fence is

circumference of circle



Now, cost of rope at is



Therefore, length of the rope requires to makes rounds of fence is 132 m and cost of rope at is Rs 528

Question: 5 From a circular sheet of radius , a circle of radius is removed. Find the area of the remaining sheet.(Take )

Answer: We know that

Area of circle

Area of circular sheet with radius 4 cm

Area of the circular sheet with radius 3 cm

Now,

Area of remaining sheet = Area of circle with radius 4 cm - Area od circle with radius 3 cm



Therefore, Area of remaining sheet is

Question: 6 Saima wants to put a lace on the edge of a circular table cover of diameter . Find the length of the lace required and also find its cost if one meter of the lace costs (Take )

Answer: It is given that the diameter of a circular table is 1.5m.

We know that

Circumference of circle is



Now, length of the lace required is

circumference of circle

Now, cost of lace at is



Therefore, length of the lace required is 4.71 m and cost of lace at is Rs 70.65

Question: 7 Find the perimeter of the adjoining figure, which is a semicircle including its diameter.

Answer: It is given that the diameter of semi-circle is 10 cm.

We know that

Circumference of semi circle is

Circumference of semi-circle with diameter 10 cm including diameter is



Therefore, Circumference of semi-circle with diameter 10 cm including diameter is 25.7 cm

Question: 8 Find the cost of polishing a circular table-top of diameter , if the rate of polishing is . (Take )

Answer: It is given that the diameter of a circular table is 1.6m.

We know that

Area of circle is



Now, the cost of polishing at is



Therefore, the cost of polishing at is Rs 30.144

Question: 9 Shazli took a wire of length and bent it into the shape of a circle. Find the radius of that circle. Also, find its area. If the same wire is bent into the shape of a square, what will be the length of each of its sides? Which figure encloses more area, the circle or the square? (Take )

Answer: It is given that the length of wire is 44 cm

Now, we know that

Circumference of the circle (C) =





Now,

Area of circle (A) =

- (i)

Now,

Perimeter of square(P) =





Area of sqaure =

-(ii)

From equation (i) and (ii) we can clearly see that area of the circular-shaped wire is more than square-shaped wire

Question: 10. From a circular card sheet of radius , two circles of radius and a rectangle of length and breadth are removed.(as shown in the adjoining figure). Find the area of the remaining sheet. (Take )

Answer: It is given that radius of circular card sheet is

Now, we know that

Area of circle (A) =

- (i)

Now,

Area of circle with radius 3.5 cm is



Area of two such circle is = -(ii)

Now, Area of rectangle =

-(iii)

Now, the remaining area is (i) - [(ii) + (iii)]



Therefore, area of the remaining sheet is

Question:11 A circle of radius is cut out from a square piece of an aluminium sheet of side . What is the area of the left over aluminium sheet?

(Take )

Answer: It is given that the radius of the circle is

Now, we know that

Area of the circle (A) =

- (i)

Now,

Now, Area of square =

-(ii)

Now, the remaining area is (ii) - (i)



Therefore, the area of the remaining aluminium sheet is

Question: 12 The circumference of a circle is . Find the radius and the area of the circle? (Take )

Answer: It is given that circumference of circle is

Now, we know that

Circumference of circle is =







Now, Area of circle (A) =



Therefore, radius and area of the circle are respectively

Question: 13 A circular flower bed is surrounded by a path wide. The diameter of the flower bed is . What is the area of this path?

Answer: It is given that the diameter of the flower bed is

Therefore,

Now, we know that

Area of the circle (A) =

-(i)

Now, Area of outer circle with radius(r ') = 33 + 4 = 37 cm is

-(ii)

Area of the path is equation (ii) - (i)



Therefore, the area of the path is

Question:14 A circular flower garden has an area of . A sprinkler at the centre of the garden can cover an area that has a radius of . Will the sprinkler water the entire garden? (Take )

Answer: It is given that the radius of the sprinkler is

Now, we know that

Area of the circle (A) =

Area cover by sprinkle is



And the area of the flower garden is

Therefore, YES sprinkler water the entire garden

Question:15 Find the circumference of the inner and the outer circles, shown in the adjoining figure? (Take )

Answer: We know that

Circumference of circle =

Now, the circumference of the inner circle with radius (r) = is



And the circumference of the outer circle with radius (r ') = 19 m is



Therefore, the circumference of inner and outer circles are respectively

Question:16 How many times a wheel of radius must rotate to go ? (Take )

Answer: It is given that radius of wheel is

Now, we know that

Circumference of circle =



Now, number of rotation done by wheel to go 352 m is



Therefore, number of rotation done by wheel to go 352 m is 200

Question: 17 The minute hand of a circular clock is long. How far does the tip of the minute hand move in hour. (Take )

Answer: It is given that minute hand of a circular clock is long i.e. ( r = 15 cm)

Now, we know that one hour means a complete circle of minute hand

Now,

Circumference of circle =



Therefore, distance cover by minute hand in one hour is 94.2 cm

NCERT Solutions for Class 7 Maths Chapter 11 Perimeter and Area Topic 11.6

Question:(i) Convert the following:

Answer: 1 cm = 10 mm

therefor

Question:(ii) Convert the following:

Answer: ha represents hectare

1 ha is 10000 m 2

therefor

Question:(iii) Convert the following:

Answer: 1m = 100cm

Therefor

Question:(iv) Convert the following:

Answer: The conversion is done as follows

NCERT Solutions for Class 7th Maths Chapter 11 Perimeter and Area Exercise 11.4

Question: 1 A garden is long and broad. A path wide is to be built outside and around it. Find the area of the path. Also find the area of the garden in hectare.

Answer: It is given that the garden is long and broad

It is clear that it is rectangular shaped with

We know that the area of the rectangle is

-(i)

Now, length and breadth of the outer rectangle is


Area of the outer rectangle is

-(ii)

Area of the path is (ii) - (i)



Therefore, the area of the path is

Question: 2 A wide path runs outside and around a rectangular park of length and breadth . Find the area of the path.

Answer: It is given that park is long and broad

It is clear that it is rectangular shaped with

We know that area of rectangle is

-(i)

Now, length and breadth of outer rectangle is


Area of the outer rectangle is

-(ii)

Area of path is (ii) - (i)



Therefore, area of path is

Question: 3 A picture is painted on a cardboard long and wide such that there is a margin of along each of its sides. Find the total area of the margin

Answer: It is given that cardboard is long and wide such that there is a margin of along each of its sides

It is clear that it is rectangular shaped with

We know that the area of the rectangle is

-(i)

Now, the length and breadth of cardboard without margin is

Area of cardboard without margin is

-(ii)

Area of margin is (i) - (ii)



Therefore, the area of margin is

Question: 4(i) A verandah of width is constructed all along outside a room which is long and wide. Find: the area of the verandah

Answer: It is given that room is long and wide.

It is clear that it is rectangular shaped with

We know that the area of the rectangle is

-(i)

Now, when verandah of width is constructed all along outside the room then length and breadth of the room is

Area of the room after verandah of width is constructed

-(ii)

Area of verandah is (ii) - (i)



Therefore, the area of the verandah is

Question: 4(ii) A verandah of width is constructed all along outside a room which is long and wide. Find: the cost of cementing the floor of the verandah at the rate of .

Answer: It is given that room is long and wide.

It is clear that it is rectangular shaped with

We know that the area of the rectangle is

-(i)

Now, when verandah of width is constructed all along outside the room then length and breadth of the room is

Area of the room after verandah of width is constructed

-(ii)

Area of verandah is (ii) - (i)



Therefore, area of verandah is

Now, the cost of cementing the floor of the verandah at the rate of is



Therefore, cost of cementing the floor of the verandah at the rate of is

Question: 5(i) A path wide is built along the border and inside a square garden of side . Find: the area of the path.

Answer: Is is given that side of square garden is

We know that area of square is =

-(i)


Now, area of square garden without 1 m boarder is

-(ii)

Area of path is (i) - (ii)



Therefore, area of path is

Question: 5(ii) A path wide is built along the border and inside a square garden of side . Find: the cost of planting grass in the remaining portion of the garden at the rate of

Answer: Is given that side of square garden is

We know that area of square is =

-(i)


Now, area of square garden without 1 m boarder is

-(ii)

Area of path is (i) - (ii)



Therefore, area of path is

Now, cost of planting grass in the remaining portion of the garden at the rate of is



Therefore, cost of planting grass in the remaining portion of the garden at the rate of is

Question: 6 Two cross roads, each of width , cut at right angles through the centre of a rectangular park of length and breadth and parallel to its sides. Find the area of the roads. Also find the area of the park excluding cross roads. Give the answer in hectares.

Answer:


It is given that width of each road is and the length of rectangular park is and breadth is

Now, We know that area of rectangle is =

Area of total park is

-(i)

Area of road parallell to width of the park ( ABCD ) is

-(ii)

Area of road parallel to length of park ( PQRS ) is

-(iii)

The common area of both the roads ( KMLN ) is

-(iv)

Area of roads =

-(v)

Now, Area of the park excluding crossroads is =

Question: 7(i) Through a rectangular field of length and breadth , two roads are constructed which are parallel to the sides and cut each other at right angles through the centre of the fields. If the width of each road is , find the area covered by the roads.

Answer:

It is given that the width of each road is and length of rectangular park is and breadth is

Now, We know that area of rectangle is =

Area of total park is

-(i)

Area of road parallell to width of the park ( ABCD ) is

-(ii)

Area of road parallel to length of park ( PQRS ) is

-(iii)

The common area of both the roads ( KMLN ) is

-(iv)

Area of roads =



Therefore, the area of road is

Question: 7(ii) Through a rectangular field of length and breadth , two roads are constructed which are parallel to the sides and cut each other at right angles through the centre of the fields. If the width of each road is .find the cost of constructing the roads at the rate of .

Answer:


It is given that the width of each road is and the length of rectangular park is and breadth is

Now, We know that area of rectangle is =

Area of the total park is

-(i)

Area of road parallel to the width of the park ( ABCD ) is

-(ii)

Area of road parallel to the length of park ( PQRS ) is

-(iii)

The common area of both the roads ( KMLN ) is

-(iv)

Area of roads =



Now, the cost of constructing the roads at the rate of is



Therefore, the cost of constructing the roads at the rate of is

Question: 8 Pragya wrapped a cord around a circular pipe of the radius (adjoining figure) and cut off the length required of the cord. Then she wrapped it around a square box of side (also shown). Did she have any cord left?

Answer: It is given that the radius of the circle is 4 cm

We know that circumference of circle =



And perimeter of the square is



Length of cord left is

Therefore, Length of cord left is

Question: 9(i) The adjoining figure represents a rectangular lawn with a circular flower bed in the middle. Find: the area of the whole land.

Answer: We know that area rectangle is =

Area of rectangular land with length 10 m and width 5 m is



Therefore, area of rectangular land with length 10 m and width 5 m is

Question: 9(ii) The adjoining figure represents a rectangular lawn with a circular flower bed in the middle. Find: the area of the flower bed.

Answer: We know that area of circle is =

Area of flower bed with radius 2 m is



Therefore, area of flower bed with radius 2 m is

Question: 9(iii) The adjoining figure represents a rectangular lawn with a circular flower bed in the middle. Find: the area of the lawn excluding the area of the flower bed.

Answer: Area of the lawn excluding the area of the flower bed = Area of rectangular lawn - Area of flower bed

=

Therefore, area of the lawn excluding the area of the flower bed is

Question: 9(iv) The adjoining figure represents a rectangular lawn with a circular flower bed in the middle. Find: the circumference of the flower bed

Answer: We know that circumference of the circle is =

Circumference of the flower bed with radius 2 m is



Therefore, the circumference of the flower bed with radius 2 m is

Question: 10(i) In the following figure, find the area of the shaded portion:

Answer: Area of shaded portion = Area of the whole rectangle ( ABCD ) - Area of two triangles ( AFE and BCE)

Area of the rectangle with length 18 cm and width 10 cm is



Area of triangle AFE with base 10 cm and height 6 cm is



Area of triangle BCE with base 8 cm and height 10 cm is



Now, Area of the shaded portion is



Question: 10(ii) In the following figure, find the area of the shaded portion:

Answer: Area of shaded portion = Area of the whole square (PQRS) - Area of three triangles ( PTQ, STU and QUR )

Area of the square with side 20cm is



Area of triangle PTQ with base 10 cm and height 20 cm is



Area of triangle STU with base 10 cm and height 10 cm is



Area of triangle QUR with base 20 cm and height 10 cm is



Now, Area of the shaded portion is



Question: 11 Find the area of the quadrilateral . Here, and

Answer: Area of quadrilateral ABCD = Area of triangle ABC + Area of tringle ADC

Area of triangle ABC with base 22 cm and height 3 cm is



Area of triangle ADX with base 22 cm and height 3 cm is



Therefore, the area of quadrilateral ABCD is =


Perimeter And Area Class 7 Maths Chapter 11-Topics

  • Squares And Rectangles
  • Triangles As Parts Of Rectangles
  • Generalising For Other Congruent Parts Of Rectangles
  • Area Of A Parallelogram
  • Area Of A Triangle
  • Circles
  • Circumference Of A Circle
  • Area Of Circle
  • Conversion Of Units
  • Applications

NCERT Solutions for Class 7 Maths Chapter Wise

Chapter No.

Chapter Name

Chapter 1

Integers

Chapter 2

Fractions and Decimals

Chapter 3

Data Handling

Chapter 4

Simple Equations

Chapter 5

Lines and Angles

Chapter 6

The Triangle and its Properties

Chapter 7

Congruence of Triangles

Chapter 8Comparing quantities

Chapter 9

Rational Numbers

Chapter 10

Practical Geometry

Chapter 11

Perimeter and Area

Chapter 12

Algebraic Expressions

Chapter 13

Exponents and Powers

Chapter 14

Symmetry

Chapter 15Visualising Solid Shapes

NCERT Solutions for Class 7 Subject Wise

NCERT Solutions for Class 7 Maths

NCERT Solutions for Class 7 Science

Some important point from NCERT solutions for Class 7th Maths chapter 11 Perimeter and Area

Area of a triangle: If the base length and height of a triangle are given

The perimeter of the triangle:- Perimeter will be equal to the sum the sides of the triangle

a- First side of the triangle

b- Second side of the triangle

c- Third side of the triangle

Area of Circles:-

r-> Radius of the circle

Circumference of Circle:-

r-> Radius of the circle

Area of a parallelogram:

b-> base length

h-> height

Tip- You shouldn't just memorize the formulas, also understand the concept of how these formulas are derived. If you go through solutions of NCERT Solutions for Class 7 , you will understand all these concepts very easily.

Happy Reading!!!

Also Check NCERT Books and NCERT Syllabus here:

  • NCERT Syllabus Class 7 Maths
  • NCERT Books Class 7
  • NCERT Syllabus Class 7