Question

find the degree measure of an angle which is equal to its supplement.

Answer 1

The degree measure of an angle which is equal to its supplement is ∠90°

Supplementary angle: Two angles which together forms an angle of 180°

Example: if we have 50°, 130° is its supplementary angle.

Since we need an angle which is equal to it supplementary that is only possible for 90°

If we have 90°,its supplementary angle is also 90°, 90°+90°=180°

Answer 2

90°
x+x= 180
2x=180
x=180/2= 90°
90° supplement is equal to itself