Find the dimensions of a rectangle

Question 1

The length and the breadth of a rectangle are in the ratio 3 : 5. If its perimeter is 32 m, find its dimensions?

Explanation

Let, length and breadth be 3y m and 5y m

Since, perimeter of rectangle = 2 (l+b) units

= 2 ( 3y + 5y ) m

= ( 2 x 8y ) m

= 16y m

But, perimeter of rectangle = 32 m

Since, 16y = 32

y = 32/16

y = 2

So, length = ( 3 x 2 ) m = 6 m

breadth = ( 5 x 2 ) m = 10 m




Question 2

The length and the breadth of a rectangle are in the ratio 4 : 5. If its perimeter is 3 m 60 cm, find its dimensions?

Explanation

Let, length and breadth be 4y cm and 5y cm

Since, perimeter of rectangle = 2 (l+b) units

= 2 ( 4y + 5y ) cm

= ( 2 x 9y ) cm

= 18y cm

But, perimeter of rectangle = 3 m 60 cm = 360 cm

Since, 18 y = 360

y = 360/18

y = 20

So, length = ( 4 x 20 ) cm = 80 cm

breadth = ( 5 x 20 ) cm = 100 cm

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