Question

If the diagonal of a square is $10cm$, then its area is

Answer 1

By Pythagoras theorem

$B{D}^2=x^2+x^2$

$BD=\sqrt{2}x$

$\sqrt{2}x=10cm$ $x=\frac{10}{\sqrt{2}}$

Area =$x^2={\left(\frac{10}{\sqrt{2}}\right)}^2=50c{m}^2$