Create 2 prisms with a volume of 300m3.

I will use two different type of prisms:

Triangular prism:

The volume is equal to the area of the triangle multiplied by the heigt of the prism.

So:

300m^3 = A*H

Suppose that the triangle is a triangle rectangle with two equal cathetus of lenght L = 6m, then the area of the triangle is:

A = 6m*6m/2 = 18m^2

300m^3 = 18m^2*H

H = 300/18 m = 16.6m

So this prism is a triangular prism where the area of the triangular face is 18m^2 and the height is 16.6m

Rectangular prism:

Here the volume of the prism is:

V = W*H*L

Where W is the width, H is the heigth and L is the length.

300m = W*H*L

now we can assign values to two of the values and then find the other value.

Suppose W = 30m, H = 5m

300m^3 = 30m*5m*L = 150m^2*L

L = 300/150 m = 2m

So this prism has a width of 30m, a height of 5m and a length of 2m.