Mechanical Engineering Question:

You cannot convert feet into square feet; they are two entirely different and incompatible units. Converting feet to square feet is like converting apples to oranges.

A linear foot is a unit of distance. A square foot is a unit of area. If you have a rectangular surface, you can compute the area in square feet by multiplying the length in feet by the width in feet. For example, a rectangular patio that is 12 feet wide by 15 feet long has an area of 12 x 15 = 180 square feet.