To determine the number of square yards to be protected, multiply 16 feet by 18 feet to determine the number of square feet, 288. Then divide 288 by 9 to convert square feet to square yards (1 square yard = 3 feet × 3 feet = 9 square feet). Multiply the quotient, 32 square yards, by the cost of protection per square yard, 0.65, to get the correct answer, 20.80. Remember to perform all the steps in a calculation.