1) A rectangular pool is 60 feet long by 30 feet wide. The shallow end is 4 feet deep and the deep end is 8 feet deep. Find the surface area and the volume.
2) A circular spa has a 10 foot diameter and a constant depth of 4 feet deep. Find the surface area and the volume.
3) A rectangular pool has a swimming area and a diving well. The swimming area is 75 feet long by 25 feet wide and is 3 feet deep to 5 feet deep. The diving well is 25 feet long by 25 feet wide and has a constant depth of 10 feet deep. Find the total volume. (Hint: Split the pools, then find the volume of each and add totals.)
FORMULAS
Surface Area (Circle): Radius x Radius x 3.14 (Radius = Diameter / 2)
Surface Area (Rectangle/Square): Length x Width
Volume (Circle/Rectangle/Square): Surface Area x Average Depth x 7.5
Average Depth: (Shallow Depth + Deep Depth) ÷ 2
(Note: Constant Depth = Average Depth)
EXAMPLE
A rectangular pool is 50 feet long by 20 feet wide. The shallow end is 3 feet deep and the deep end is 7 feet deep. Find the surface area and the volume.
Surface Area = Length x Width
Surface Area = 50 feet x 20 feet
Surface Area = 1,000 square feet
Volume = Surface Area x Average Depth x 7.5
Volume = 1,000 x Average Depth x 7.5
Average Depth = (Shallow Depth + Deep Depth) ÷ 2
Average Depth = (3 + 7) ÷ 2
Average Depth = 10 ÷ 2
Average Depth = 5
Volume = 1,000 x 5 x 7.5
Volume = 37,500 Gallons
ANSWERS
1. Surface Area = 1,800 square feet Volume = 81,000 Gallons
2. Surface Area = 78.5 square feet Volume = 2,355 Gallons
3. Total Volume = 103,125 Gallons
