Remark The 68° will get you 1/2 the base if you use the right trig function. After that, all you need do is use the Cone Formula for Volume.
Step One Find 1/2 the base. The height and 1/2 the base are in a right triangle. Put into more formal language Tan(68°) = Opposite side / Adjacent Side
Givens Angle = 68° Opposite Side = 4.2 feet.
Substitute Adjacent side = opposite Side / Tan(68°) Adjacent side = 4.2 / Tan(68°) Adjacent side = 1.697 feet
Step Two Find the Volume
Formula V = 1/3 pi r^2 h
Givens V = ??? pi = 3.14 r = 1.6969 h = 4.2 feet.
Solve V = 1/3 3.14 * 1.6969^2 * 4.2 V = 12.66 cubic feet.
