Question

If the area of a square is $100$ $c{m}^2$, what is the area of that square when its side is doubled?

• A. $50$ $c{m}^2$
• B. $200$ $c{m}^2$
• C. $300$ $c{m}^2$
• D. $400$ $c{m}^2$

Answer 1

The correct option is D $400$ $c{m}^2$

Consider the given square,
Its area is given as $100$ $c{m}^2$
So,
$100$ $c{m}^2$ $=$ side $\times$ side
$⟹$ side $=10cm$
So, the length of its sides would be $10cm$.

Hence, the double of $10$, that is $20$ is the side length of the new square.

Now to find the area,
Area $=$ side $\times$ side
$=20$ $\times$ $20$ = $400$ $c{m}^2$