Let's imagine we enclosed the entire shape in a 15 inch wide, 21 inch tall rectangle, area 315 sq inches.
From that rectangle we have to take away the 3x6 bottom left corner, and a strip 21-6=15 inches long and 3 inches wide on the right.
A = 15×21 - 3×6 - 3×15 = 315 - 63 = 252 sq in
Answer: D. 252 inches squared, last choice
