geometry work?

Question

http://i12.tinypic.com/2ex3dsh.jpg

please answer a, b, c, and d

Answer 1

a) would be definition of rt triangles
b) must be isosceles triangle theorem
c) reflexive property of congruence
d) it's set up to be HL, but that's needlessly complex. from angle A = angle C, the 2 right angles, and DB in common, the triangles are congruent by AAS.