Page 341 - Math Smart - 7

If the rectangle is a square, then both sides are the lengths.
The formula for the area of a square then becomes as follows:
length (/)
Area of a square = length x length
= /x /

length (/)

Find the missing side In each rectangle.
? m
a) b)

Area = 84 cm 7 cm Area = 72 m 9 m

Solution
a) Area of rectangle = 84 cm^ b) Area of rectangle = 72 m^
We can use the formula to
Length of rectangle = ? cm Length of rectangle = 9 m find the missing side.

Width of rectangle = 7 cm Width of rectangle = ? m
? X 7 = 84 9 X ? =72
? = 84 -r 7 ? = 72 9
= 12 = 8
The length of the rectangle The length of the rectangle
is 12 cm. is 8 m.

Example 4

O Calculate the breadth of © Calculate the length of © Calculate the length of
the rectangle. the rectangle. the square.

9 cm

25 m"
18 cm 4 mm 32 mm'

Solution Solution Solution
A=lx b A =lx b A = / X /
^B = 9xb 32 = 1 X A 25 = /'
l = V2S
= 2 = 8 = 5

The breadth is 2 cm. The length is 8 mm. The length is 5 m.