Assignment:
A rectangular building whose depth is twice its frontage is divided into two parts, a front portion and a rear portion, by a partition that is 30 feet from and parallel to the front wall.
Identify the front (width) by the letter "x" and write the following:
- Depth (length) of the building
- Length of the rear portion
- Write an expression for the area of the rear portion
Hint: Make a sketch on a scratch paper to describe the dimensions.
Provide complete and step by step solution for the question and show calculations and use formulas.