You will need
Measure internal or external diameter of the pipe, and the length of the circumferential section.
Find the radius of the pipe . If you want to calculate the internal volume, you need to find the inner radius. To calculate the volume that is occupied by the body, you need to calculate the outside radius. Divide the diameter by two. R=D/2. You can also use the length of the cross section: R=L/6,28318530. Here L is the length of the circumference, and the number is twice PI.
Calculate the cross-sectional area of the pipe. The radius value to construct a square, multiply it by PI. The cross-sectional area will be expressed in the same units as the radius value. For example, the radius is represented in centimeters. In this case, the cross-sectional area is expressed in square centimeters. The formula that calculates the cross-sectional area: S = R2*PI, where S is the desired area and R2 is the radius.
Find the volume of the pipe. To do this, multiply the length of pipe to the area of its cross section. Formula: V=S*L, where V is the volume of the pipe, S is the cross – sectional area, L is the length.
Similarly, find the volume of all tubes (if they have different diameters).
You must make sure that the length of the pipe and the radius are expressed in the same units of measurement. Otherwise you will get wrong value. Usually all calculations are done in centimeters and square centimeters.
If during the calculation you use a calculator in his memory can be recorded twice the number PI. Then we will quickly calculate the values of several volumes if you need to find the volume of the pipes with different diameters. Also in the memory of the calculator or computer, you can make ready-made formula for quick to make the necessary calculations. If you often work with mathematical formulas, can be downloaded from the Internet a special program.