△ABC is a right triangle with right angle at B. A perpendicular BD is drawn from B to the hypotenuse AC.
a. (a) Prove that △ADB is similar to △ABC.
b. (b) Prove that △BDC is similar to △ABC.
c. (c) Using the results of parts (a) and (b), establish the relation AC2=AB2+BC2.
d. (d) If AB=6cm and BC=8cm, calculate the length of AC using the relation obtained in part (c).