A and D have the same measure, let's call that x C and B have the same measure, let's call that y That would mean 2x+2y=360 Since C is equal to 4 times A, that means y=4x 2x+2(4x)=360 2x+8x=360 10x=360 x=36 A and D both equal 36 degrees B and C both equal 36 times 4, or 144 degrees