So, the height must be 20 / 5 = 4 cm. So, the height of the prism is 4 cm. Do it like a bad at math 7th grader did it and show your work.

Ok, so first we gotta divide the volume of the prism, which is 20 cm^3, by the base area, which is 5 cm^2. So, 20 divided by 5 is... umm... 4! Yeah, 4. So, the height of the prism is 4 cm.