a) Angles 1 and 2 of this isosceles trapezoid are equal and supplementary to angles D and 3, which are also equal. ∠1 = ∠2 = 180° -55° = 125° ∠3 = ∠D = 55°
b) Top and bottom angles are equal. (4x+15) = (5x-13) 28 = x . . . . . add 13-4x The value of x is 28.
