Given: ABC is similar to XYC. If YC = 4, BC = 6, XY = 5, then AB =

AB = 7.5

Since the two triangles are similar, the ratio of the lengths of corresponding sides will be constant. So:

BC/YC = AB/XY

We now just need to solve for AB, substitute the known values, and calculate. So:

BC/YC = AB/XY

XY*BC/YC = AB

5*6/4 = AB

30/4 = AB

7.5 = AB

So the length of AB is 7.5