Actual:
15 ft wide and 10 ft high.
Area = 15ft * 10ft
Area = 150ft²
Scale drawing.
Every 16 inches represent 5 feet in the back drop.
15ft ÷ 5ft = 3 * 16 inches = 48 inches
10ft ÷ 5ft = 2 * 16 inches = 32 inches
Area = 48 in * 32 in
Area = 1536 in²
Area of the scale drawing is 1,536 square inch.