A. Cross multiply. 12*20 = 16x 240 = 16x (divide by 16 on both sides) 15 = x B. Do the same as part A. just you have to make the ratio this time. x/20 = 6/8 Cross multiply. 6*20 = 8x 120 = 8x (divide by 8 on both sides) 15 = x C. The answers to part A and B are the same because the triangles are similar.