## Basic College Mathematics (9th Edition)

The third angle in the right angled triangle is $24˚$
Let $x =$ third angle in the right angled triangle $90 + 66 + x = 180$ (Right angled triangle means that one of the angles is $90˚$ and the other is given. Angles in a triangle add to $180˚$) $156 + x = 180$ $x = 24˚$ Therefore the third angle in the right angled triangle is $24˚$