The expression representing the complement of an angle (x): (90 - x) : The expression representing the supplement of an angle (x) (180 - x) : "the complement of an angle is 18 degrees more than 1/3 its supplement." (90 - x) = (180-x) + 18 : 90 - x = 60 - x + 18; found one third of 180 : 90 - x = 78 - x :
90 - 78 = -x + x : 12 = +x Multiply equation by 3 to get rid of the denominator 3(12) = 3*x 36 = 2x x = x = 18 degrees
