The supplement of a 65 degree angle has a measure of?

Supplementary angles are angles whose sums =180 degrees.

You have a 65 degree angle + it's supplementary angle = 180 degrees.

So, to find the supplementary angle, subtract 65 from 180.

180 - 65 = supplementary angle.

115 = supplementary angle.

To check, add the angles together. 65 + 115 = 180 (check)

(Also, you might be working with complimentary angles.

Complimentary angles are angles whose sum = 90 degrees.)