How much water will a water main hold if its 18 inches in diameter and 2 miles long?

To calculate the volume of water a water main will hold, we can use the formula for the volume of a cylinder: V = πr²h. First, convert the diameter to radius (18 inches diameter means a radius of 9 inches or 0.75 feet). The length of the water main is 2 miles, which is 10,560 feet. Plugging these values into the formula, we find the volume is approximately 43,500 cubic feet, which is about 326,000 gallons of water.