Answer
The third angle in the right angled triangle is $24˚$
Work Step by Step
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 $24˚$
