Answer:
235.75 square feet
Explanation:
15 inches on all sides, means 30 inches more on side a and side b.
30 inches converted to feet is 2.5.
side a: 18 feet + 2.5 feet =20.5 feet
side b: 9 feet + 2.5 feet = 11.5
multiply both sides
20.5 * 11.5 = 235.75 square feet