∠A and \angle B∠B are supplementary angles. If m\angle A=(3x+18)^{\circ}∠A=(3x+18)
∘
and m\angle B=(5x+2)^{\circ}∠B=(5x+2)
∘
, then find the measure of \angle A∠A.
Start with the equation 8x+20=180 and solve for x which equals x=20. You then substitute for x with the equation for angle A. A=3(20)+18 which makes angle A = 78
