How is the volume of a pipe calculated?

The volume of a pipe is calculated using the formula that represents the volume of a cylinder. A pipe essentially functions as a cylindrical shape, where the key parameters are its diameter and length.

The correct formula, which takes into account the radius of the cylinder, is expressed as:

[ \text{Volume} = \pi r^2 h ]

where ( r ) is the radius and ( h ) is the height (or length) of the cylinder. Since the radius is half of the diameter, and the area of the circle (cross-section of the pipe) is ( \pi r^2 ), you can also express it using the diameter.

By substituting the radius in terms of diameter (where ( r = \frac{Diameter}{2} )), you arrive at:

[ \text{Volume} = \pi \left(\frac{Diameter}{2}\right)^2 Length = \pi \frac{Diameter^2}{4} Length ]

However, this can also be conveniently represented as:

[ \text{Volume} = 0.785 \times Diameter^2 \times Length ]

Thus, the correct choice takes the necessary geometric relationships into account