Hey Guys!

For NUMBER 9)

I'm trying to find the answer but I don't know how to set up this equation.

Since Angle A = Angle C

I am setting up the equation as 2x/3 = x/2 + 20

I take out the fractions with 6 and I get 4x = 3x + 20

then I get x = 20

Doesn't seem to work though. The answers are m∠A = m∠C = 80°;m∠B = m∠D = 100°