Seth is using the figure shown below to prove pythagorean theorem using triangle similarity.

in the given triangle abc, angle a is 90° and segment ad is perpendicular to segment bc.

the figure shows triangle abc with right angle at a and segment ad. point d is on side bc.

part a: identify a pair of similar triangles. (2 points)

part b: explain how you know the triangles from part a are similar. (4 points)

part c: if db = 9 and dc = 4, find the length of segment da. show your work. (4 points)