Question

$\text{The length of the side of a square with an area of}$
$1,600m^{2}is$ ____.

• A. 80 m
• B. 44 m
• C. 30 m
• D. 40 m

Answer 1

The correct option is D 40 m

If the side of square is a, its area is $a^2$.

According to question,

$\text{Area of the square}=1600m^2$

$\therefore a^2=1600$
$\Rightarrow a^2=2\times 2\times 2\times 2\times 10\times 10$
$a=\sqrt{\underset{–}{2\times 2}\times \underset{–}{2\times 2}\times \underset{–}{10\times 10}}$
$\downarrow \downarrow \downarrow$
$\text{2}\times \text{2}\times \text{10}$

$\therefore a=40m$

So, the area of the square is 40 m.