1. Find the Area of a Square Example 1 Find the area of the square. SOLUTION Use the formula for the area of a square and substitute 9 for s. A = s 2 Formula for the area of a square = 92= 92 Substitute 9 for s. = 81 Simplify. The area of the square is 81 square feet. ANSWER

2. Find the Area of a Rectangle Example 2 Find the area of the rectangular pool. Use the formula for the area of a rectangle. Substitute 24 for b and 16 for h. SOLUTION A = bh Formula for the area of a rectangle = 24 · 16 Substitute 24 for b and 16 for h. = 384 Multiply. The area of the pool is 384 square feet. ANSWER

3. Find the Height of a Rectangle Example 3 Use the formula for the area of a rectangle and substitute 54 for A and 9 for b. SOLUTION A = bh Formula for the area of a rectangle 54 = 9h Substitute 54 for A and 9 for b. 6 = h Divide each side by 9. The height of the rectangle is 6 inches. ANSWER The rectangle has an area of 54 square inches. Find its height.

4. Checkpoint Area of Squares and Rectangles Find the area of the quadrilateral. 1. 2. 3. A rectangle has an area of 52 square meters and a height of 4 meters. Find the length of its base. 4. ANSWER 121 m 2 ANSWER 12 ft 2 ANSWER 26.55 yd 2 ANSWER 13 m