I need help :( If you are not sure please say so because if I get it wrong it sets me back about an hour. I am also throwing 40 point out.

Note that C-B is considered the hypotenuse of the of traingle. Therefore, according to the acronym SOH CAH TOA, Cos C = Adjacent/ Hypotenuse, where the adjacent is 8√34 and the hypotenuse is given by by pythagoreas theorem (a²+b² = c²) or c=√(a²+b²) → c=√4352

Then Cos C = (8√34) /(√4352) → this simplifies into √2 on the top and 2 on the bottom once we simplify.

Final

square pyramid

step-by-step explanation:

square prism looks like nothing like that

triangular prism has a rectangular base instead of a square base

tetrahedron has a triangular base