Question

The sides of a rectangle are in the ratio 4 : 5 and its perimeter is 180 cm. Find its sides.

Answer 1

Let the length be $4x$ cm and the breadth be $5x$ cm.
Perimeter of the rectangle =180 $cm$
Perimeter of the rectangle=$2(l+b)$

$$\begin{gathered} 2(l+b)=180 \\ \Rightarrow 2(4x+5x)=180 \\ \Rightarrow 2\left(9x\right)=180 \\ \Rightarrow 18x=180 \\ \Rightarrow x=10 \end{gathered}$$

$$\begin{gathered} \therefore \mathrm{Length}=4x\mathrm{cm}=4\times 10=40\mathrm{cm} \\ \mathrm{Breadth}=5x\mathrm{cm}=5\times 10=50\mathrm{cm} \end{gathered}$$