What You Need:

• Pencil and paper
• Calculator

What You and Your Child Will Do:

A new circular swimming pool with a 30-foot diameter is enclosed by a square fence that measures 42 feet on a side. Sod was put down around the pool and within the fence so that the swimmers can step out of the pool and onto soft grass.
2. Use the formulas:
Perimeter of a square = 4s
Area of a square = s2
Circumference of a circle = d
Area of a circle = πr2
3. Challenge your child with the following:
• What is the question whose answer is 168 feet?
Answer: “What is the length of the fencing?” (P = 4s, or 4 x 42 = 168 ft)
• What is the question whose answer is 1,764 square feet?
Answer: “What is the area enclosed by the fence?” (A = s2, or 42 x 42 = 1,764 ft2)
• What is the question whose answer is 188.4 feet
Answer: “What is the circumference of the pool?” (C = d, or 2 x 3.14 x 30 = 188.4 ft)
• What is the question whose answer is 706.5 square feet?
Answer: “What is the area of the pool?” (A = πr2, or 3.14 x 152 = 706.5 ft2)
• What is the question whose answer is 1,057.5 square feet?
Answer: “How much sod was put down?” (1,764 − 706.5 = 1,057.5 ft2)