Question

Find the measure of an angle whose measure is 20° less than the measure of its supplement.

Answer 1

Supplementary = angles add up to 180
Measure = 20 less

Labelled as x + (x - 20) = 180

Solve.

x + (x - 20) = 180
             2x = 200
             /2      /2
               x = 100

Angle 1:             Angle 2:
x - 20                  x
100 - 20             100
80

Therefore the angle is 80 degrees.

Proof: 80 + 100 = 180 (supplementary)
100 - 80 = 20 (80 is less than supplement (100)

Hope I helped :))))