To answer this question, first identify what shape this is. Considering the shape of the sides, you can conclude that this is a triangular prism.
Now, that you've identified the shape, you can use the equation to find the volume of a triangular prism: Base area × length.
The base area is the area of a triangle or
b= base = 14 ft
h= height = 19 ft
Plug in your information to find the base area: 1/2 × 14 × 19 = 133 ft
Now that you have your base area, multiply the value by the length (20 ft):
133 × 20 = 2660 cubic ft is your volume