Question

Help me solve for A and B!

Answer 1

Here we have one large triangle with two smaller triangles drawn inside.  The two smaller triangles are similar.

Thus, a/12 = 12/16, or   a/12 = 3/4, or 4a=36, or a = 9.  

Find b in the same way:  b/20 = 9/12 (and so on).