Question

A triangle has sides with lengths of 23 meters, 13 meters, and 18 meters. Is it a right triangle?

Answer 1

No.

Explanation:

if it were a right triangle, then `23^2 = 13^2 + 18^2`

`529 = 169 + 324?` No.

By the cos rule, `23^2 = 13^2 + 18^2 - 2 * 13 * 18 * cos theta`

`theta ne pi/2`