If anyone understands proofs, could you walk me through this? i really don't get them. any would be appreciated!

In mathematics, a proof is a deductive argument for a mathematical statement. In the argument, other previously established statements, such as theorems, can be used. In principle, a proof can be traced back to self-evident or assumed statements, known as axioms.

Just a note before I get started: The specific theorem/postulate/definition will be given in quotes. Everything else will be explanation of why we will use itLets get started  :D
b. We can use the "definition of a square" because it states that it a square, every side is congruent. We can use this because we already know that the shape is a square due to a.

c. We can use "definition of a square" again for the same reason as b.

e. We know that the hypotenuses (hypoteni?) of both triangles are congruent, and they both share a side, so we can use the "Hypotenuse Leg Theorem"

f. Because we know that the triangles are congruent, we can use the "Base Angle Theorem" to say that the angles are congruent. 

h. Because they share the same side, we can use the "Linear Pair Theorem" to say that they are supplementary angles

Hope this helped! Sorry if its a bit late. :D

Are you trying to figure out the volume?