How can the use of sine and cosine be for determining what a triangle looks like?

How do i work this problem out using the equation a=pe^rt

When a 757 passenger jet begins its descent to the ronald reagan national airport in washington, d.c., it is 3900 feet from the ground. its angle of descent is 6 degrees. how far must the plane fly to reach the run way? a. 37,106 ft b. 37,310.4 ft c. 23,456.6 ft d 2,492.7 ft

Build is 120 wide 20 feet high 48 feet long how many cubic feet and the volume