Question

A square $PQRS$ is of side $10\text{cm}$ each. Write the length of its diagonal $PR$.

Answer 1

Applying Pythagoras theorem in $△PSR$:

$P{R}^2=P{S}^2+S{R}^2$

$P{R}^2={10}^2+{10}^2$

$P{R}^2=100+100$

$PR=10\sqrt{2}\text{cm}$