A $30\text{-}60\text{-}90$ triangle is a right triangle with two acute angles – one measuring $30^{\circ }$ and one measuring $60^{\circ }$ – and one right angle.

If the shorter leg in a $30\text{-}60\text{-}90$ triangle has the length $\ell ,$ the longer leg will have the length $\sqrt{3}\cdot \ell$ and the length of the hypotenuse will be $2\ell .$