# A triangle has sides A, B, and C. Sides A and B are of lengths 2 and 1, respectively, and the angle between A and B is (pi)/2 . What is the length of side C?

May 22, 2016

$C = \sqrt{5} = 2.236$ units

#### Explanation:

As angle between $A$ and $B$ is $\frac{\pi}{2}$,

$C$ is hypotenuse

and as side $A = 2$ and side $B = 1$

using Pythagoras theorem

${C}^{2} = {A}^{2} + {B}^{2} = {2}^{2} + {1}^{2} = 4 + 1 = 5$

Hence $C = \sqrt{5} = 2.236$ units