Question

The area of a square increases by _____, if its side increases by $30\%$.

• A. $71\%$
• B. $60\%$
• C. $69\%$
• D. $30\%$

Answer 1

Answer: (C)

$69\%$

Let the original length of the side of the square $=x$ units
Then, original area $=x^2$ sq units
New length $=\frac{130x}{100}units=1.3x$ units
$\therefore$ New area $=(1.3x\times 1.3x)$ sq units
$=0.69x^2$ sq units
Increase in area $=1.69x^2$ sq units
$\%$ increase $=(\frac{0.69x^2}{x^2}\times 100)\%=69\%$