Question

Difficulty: MediumCylindrical Volume Applications

A city construction crew is installing a new cylindrical concrete drainage pipe. The interior of the pipe has a diameter of 10 feet10\text{ feet} and a length of 100 feet100\text{ feet}. Using 3.143.14 for π\pi, what is the maximum volume of water the pipe can hold when completely full, in cubic feet?

Answer: 7850 cubic feet

Answer

The pipe can hold a maximum volume of 7,850 cubic feet.
The volume of a cylinder is found by multiplying the area of its circular base by its height or length (V=πr2hV = \pi r^2 h). First, convert the given diameter of 10 feet10\text{ feet} to a radius by dividing by 22, yielding a radius of 5 feet5\text{ feet}. Next, square the radius to get 2525. Multiply this by the length (100 feet100\text{ feet}) and the approximate value of π\pi (3.143.14). 3.14×25×100=7,850 cubic feet3.14 \times 25 \times 100 = 7,850\text{ cubic feet}.

Step-by-Step Solution

1
Find the radius of the pipe.
r=10÷2=5 feetr = 10 \div 2 = 5\text{ feet}
The volume formula for a cylinder requires the radius, which is half of the diameter.
2
Apply the volume formula for a cylinder.
V=π×r2×hV = \pi \times r^2 \times h
To find the capacity of the cylindrical pipe, we must calculate its three-dimensional space, which is volume.
3
Substitute the known values into the formula.
V=3.14×52×100V = 3.14 \times 5^2 \times 100
We use the given values: radius 5 feet5\text{ feet}, height (or length) 100 feet100\text{ feet}, and π≈3.14\pi \approx 3.14.
4
Calculate the final volume.
V=3.14×25×100=3.14×2500=7850V = 3.14 \times 25 \times 100 = 3.14 \times 2500 = 7850
Squaring the radius gives 2525. Multiplying by 100100 and 3.143.14 gives the total volume in cubic feet.

Key Concept

Calculating the volume of a cylinder using the formula V=πr2hV = \pi r^2 h, ensuring the given diameter is converted to a radius before performing calculations.
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