Is this right? what is the value of x in this triangle?

With this you would use sin,cos, and tan. You use a calculator and do the inverse of it. In this situation it would be cos, since there in nothing opposite of it but there is an adjacent. The formula for cos is adjacent of hyp. and hyp. is 29, so its 15/29. When typing that into the calculator it would look like this cos^-1(15/29). Once you press enter it would give you 58.85

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