Question

The area of a rectangle is $100$ in${}^2$, if one of the sides has a length of $20$ inches, then its perimeter(in inches) is

• A. 50

Answer 1

The correct option is A 50
Given the area of the rectangle $=100{\text{in}}^2$.
One of the sides has a length $=20\text{in}$.
We know that the area of a rectangle equals product of the side lengths.
Let the length of unknown side be $l\text{in}$.
$\Rightarrow 100=l\times 20$
Dividing with $20$ on both sides:
$\Rightarrow l=\frac{100}{20}=5\text{in}$
$\therefore$ The length of the second side $=5\text{in}$.
Also, we know that the perimeter of a rectangle $=2\times ({\text{side}}_1+{\text{side}}_2)$
$\Rightarrow$ Perimeter
$=2\times (20+5)$
$=2\times 25$
$=50$ in
$\therefore$ Perimeter of the rectangle $=50$ in