Question

Find the length of a rectangle whose perimeter
is 90 cm and sides are in the ratio of 5:4
​

Answer 1

Answer:

Let the length and breadth of the rectangle be 5x and 4x

We already know that the formula for finding the perimeter of the triangle is 2(l+b)

So, 2(5x+4x)=90cm

2(9x)=90cm

18x=90cm

x= 90/18=5

x=5cm

The length will be 5×5= 25cm and the breadth will be 5×4=20cm

Answer 2

Answer : 25cm

To find : length

Given :

perimeter = 90cm

length : breadth = 5:4

Formula used : perimeter = 2(l+b)

Solution :

l : b = 5 : 4

let common factor => x

length = 5x

breadth = 4x

also

perimeter = 2(l+b)

=> 90 = 2(5x+4x)

=> 90 ÷ 2 = 9x

=> 9x = 45

=> x = 45÷9

=> x = 5

putting value of x

we get

Length = 5x = 5(5)

length = 25cm