First prove that ∆CBD ~ ∆ABC.
Each triangle has a right triangle and each
includes angle B. The triangles are similar.
You can use similar reasoning to show that ∆ACD
~ ∆ABC.
To show that ∆CBD ~ ∆ACD, begin
by showing that angleACD = angle B because they are both complementary to angleDCB. Then you can use Similarity Postulates.
I found the image of the triangle that was missing the question! Attached triangle.
