Question

Find the measure of angle Z.

Answer 1

If the angle next to 123° is x, then 123 + x = 180, therefore x = 57°. Because the angles in a triangle add up to 180, 57 + 90 + Z = 180, therefore Z = 33°

Answer 2

check the picture below.

recall that a flat-line is always 180°, and the sum of all interior angles in a triangle is 180°.