Help find missing angle??

As both lines and triangles have to have complete 180 degrees, we can deduce that the other angle by C is 130 degrees, as 180-50 is 130. Then, we add 130 to the other 35 degrees we have in the triangle, resulting in 165 degrees. From there, as we know that triangles must have 180 degrees altogether, we can find the missing angle by calculating 180-165, which results in 15.
Therefore, we know that the missing angle is 15 degrees.

2160ft^3 i think you could use a formala to you out with this in the future