So there are a number of ways to solve this one. You could A: find the area of the desk in feet, and then convert feet squared to inches squared, or B: convert feet to inches First, and then multiply to find the area. I prefer method B, the math would be: 4 x 12 = 48. 3 x 12 = 36. 48 x 36 = 1728. Your final answer should be: 1728 in².