Final answer:
No, Brad is not correct. The area of a square with a length of 9 feet is 81 square feet, not 18 square feet.
Step-by-step explanation:
No, Brad is not correct. The area of a square is found by multiplying the length of one side by itself. In this case, if the length of the square is 9 feet, the area would be 9 * 9 = 81 square feet, not 18 square feet. Brad's calculation is incorrect because he has mistakenly multiplied the length by half of itself.
Learn more about Calculating the area of a square