Question

If the length of the side of a square is ‘a’ then the length of its diagonal will be –

• A. $\sqrt{2}a$
• B. $\sqrt{2a}$
• C. $4a^2$
• D. $6a$

Answer 1

The correct option is A

$\sqrt{2}a$

A diagonal of a square divides it into two right triangles. The diagonals of the square are the hypotenuses of the triangles. We can use Pythagoras' theorem to find the length of the diagonal if we know the side length of the square.

So, length of the diagonal= $\sqrt{a^2+a^2}=\sqrt{2}a$ , where ‘a’ is the side length of the square.