In right triangle abc shown below, altitude cd is drawn to hypotenuse (ab). explain why δabc ∼ δacd.

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.

69 i think because is the only one square