If ABCD is a parallelogram and x = 5, what is D?
Angle BCA = 8(5) = 40°
Angle BAC = 4(5) = 20°
Then angle ABC = 180 - 40 - 20 = 180 - 60 = 120 °
And because opposite angles of a parralleogram are equal, then angle B =120°
