yes angles B and C are supplementary to A

Supplement Theorem: Supplements of Congruent angles are congruent

The problem is I can't figure out what the Reflexive property of Congruence is

Here are the theorems in the chapter:

4 - 2:
If the angles in a linear pair are congruent, then each of them is a right angle

4 - 3:
If two angles are complementary, then both are acute

4 - 4:
Any two right angles are congruent

4 -5:
If two right angles are both congruent and supplementary, then each is a right angle

__________________
here we go, the world is spinning
when it stops, it's just beginning

sun comes up, we laugh and we cry
sun goes down, and then we all die

Touched by his noodly appendage