Answer:
This is a prism since both sides are the same triangle,
Lets find the area of the triangle first then multiply it by the width which is 16.
20.5(base or height) x 13.3(height or base) = 272.65
272.65 divided by 2 ( x 1/2) = 136.325 is your area, now we multiply by the width.
136.325 x 16 = 2,181.2 mm3 is your volume.
Whenever coming across these types of volumes we must first find a shape and find its area then multiply it by the figure's height.
Formula area of a triangle:
B(base) x H(height) x 1/2(basically just dividing by 2)