For the answer to the question above, this question is incomplete. I've answered this question before.
Is it like this?
V = (1/3) * (area of the base) * height
If you have a pyramid with a square base, you just multiply the length of both sides together. For example, if the pyramid was 9 inches on a side, the area of the base is 9 * 9 = 81 sq. inches.
Then you multiply that by the height and finally take 1/3 of the result. For example, if the pyramid was 10 inches high, you multiply 81 sq. inches x 10 inches = 810 cubic inches. But you have to remember to take a third of that result. 810 cubic inches / 3 = 270 cubic inches.
I hope this helps