Supplementary angles add up to 180 degrees-
Let x = "the angle"
supplement angle = 2x + 12 // 12 more than twice the measurement of "the angle"
Supplement angle + "the angle" = 180 degrees
(2x + 12) + x = 180 degrees // 2x + 12 is the supplement angle
3x + 12 = 180 // Simplify
3x = 168 // Subtract 12 from both sides
x = 56 degrees // Divide both sides by 3
The measure of the angle is 56° and its supplement is 124°