How many gallons of water in a 21 foot by 4foot 6inches deep round pool?

To determine the number of gallons of water a 21-foot by 4-foot 6-inch deep round pool can hold, we need to first calculate the volume of the pool:

1. Calculate the radius (r) of the pool:

Since the diameter of the pool is 21 feet, the radius is half of that: r = 21 ft / 2 = 10.5 ft

2. Convert the radius from feet to inches:

r = 10.5 ft * 12 in / ft = 126 in

3. Calculate the pool's volume (V) using the formula for the volume of a cylinder:

V = πr²h, where π is approximately 3.14, r is the radius, and h is the height (depth) of the pool.

V ≈ 3.14 * (126 in)² * (4.5 ft * 12 in/ft)

V ≈ 3.14 * 15876 in² * 54 in

V ≈ 2,897,351.44 cubic inches.

Finally, to convert the volume in cubic inches to gallons, divide by 231 (since there are approximately 231 cubic inches in 1 gallon):

Number of gallons = 2,897,351.44 in³ / 231 in³/gallon

Number of gallons ≈ 12,542 gallons.

Therefore, a 21-foot by 4-foot 6-inch deep round pool can hold approximately 12,542 gallons of water.