Question

Please help me! Okay. So I have an independent Honors Project to do for Algebra 2. I have to model with Polynomials. Here's the problem:
You work for the BeeSwaks Candle Company and have been asked to update two of the company’s earliest candle designs, the Brick and the Egyptian. The original Brick was a cube 8 centimeters on a side. The original Egyptian was a pyramid 21 centimeters tall with a square base 10 centimeters on a side.
You have been asked to work with the following guidelines: The Brick: Shape is a rectangular prism. Dimensions can vary, but the height has to be 1cm less than the side length of the base. The Egyptian: Shape is a right square pyramid. Same dimensions as the brick. Height is 21 cm.
Question 1: 1. Create a labeled diagram of the Brick. Use x to represent the length of a side of the base of the candle. Then write an equation for the volume of the candle in terms of x. Write the polynomial in standard form.
I'm not necessarily asking for the answer, just please walk me through it! Thanks in advance. (: