20B
MATHEMATICS
It is given that
Triangles
Part of two
11.2.2
Cr
or
the square
Arca of the rectangle 1600 cm. breadth of the rectangle - 25 cm
Take a rectangle of sidesse.
triangles (Fig 11.7)
Superpose one triangle on the ter
Are they exactly the same
Can you say that both the trades
Are the triangles comunient'
What is the area of each of these des
You will find that sum of the was
So, the perimeter of the rectangle is 178 cm oven though its area is the same talen
rectangle. Both the triangles are equal
The area of each angle
The length and the breadth of a rectangular piece of land are 500 m and 30 m
(ii) the cost of the land, if Im? of the land costs 10.0XX).
Find the breadth of a rectangular plot of land, if its area is 440 m² and the length is
The perimeter of a rectangular sheet is 100 cm. If the length is 35 cm, find its breath
5. The area of a square park is the same as of a rectangular park. If the side of the
square park is 60 m and the length of the rectangular park is 90 m, find the breadth of
A wire is in the shape of a rectangle. Its length is 40 cm and breadth is 22 cm.
same wire is rebent in the shape of a square, what will be the measure of eact
7. The perimeter of a rectangle is 130 cm. If the breadth of the re
The area of the rectangle - The area of the square
Area of the rectangle = 7xb
1600 = 1x 25
1600
164 cm
or
25
So, the length of rectangle is 64 cm.
Perimeter of the rectangle = 2 (1 + b) = 2 (64 +25) cm
= 2 x 89 cm = 178 cm
1.
respectively. Find
(1)
its area
2.
3.
22 m. Also find its perimeter.
4.
Also find the area.
the rectangular park.
6.
Also find which shape encloses more area?
EXERCISE 11.1
a square of
Find the area of a square park whose perimeter is 320 m.
Take
Are the four
Are they
What is
8.
30 cm, find its length. Also find the area of the rectangle.
A door of length 2 m and breadth Im is fitted in a wall. T
wall is 4.5 m and the breadth is 3.6 m (Fig11.6). Find
washing the wall, if the rate of white washing the w
Fig 11.6
Answers
Perimeter and Area
11.1 INTRODUCTIONQ.1
In Class VI, you have already learnt perimeters of plane figures and areas of squares and rectangles. Perimeter is the distance around a closed figure while area is the part of plane or region occupied by the closed figure.
In this class, you will learn about perimeters and areas of a few more plane figures.
11.2 SQUARES AND RECTANGLES
Ayush and Deeksha made pictures. Ayush made his picture on a rectangular sheet of length 60 cm and breadth 20 cm while Deeksha made hers on a rectangular sheet of length 40 cm and breadth 35 cm. Both these pictures have to be separately framed and laminated.
Who has to pay more for framing, if the cost of framing is 5 3.00 per cm?
If the cost of lamination is 5 2.00 per cm2, who has to pay more for lamination?
For finding the cost of framing, we need to find perimeter and then multiply it by the rate for framing. For finding the cost of lamination, we need to find area and then multiply it by the rate for lamination.