longer leg of triangle = sqrt(20^2 - 10^2) = 10sqrt(3)
Volume = Base * Height
= (10 * 10sqrt(3)/2) * 16
= 800sqrt(3) ft^3 or 1358.64 ft^3
Find height with pythagorean theorem
Sqrt (20^2 - 10^2= sqrt 300
area of trainagle = 1/2 b * h
= 1/2 10 * sqrt 300
and multiply by the 'depth' of 16 ft to find the volume
1/2 * 10 * sqrt300 * 16 = 1385.64 ft3