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How Do You Find the Size of a Cylinder?

Published in Cylinder Volume Calculation 3 mins read

When determining the 'size' of a cylinder, it most commonly refers to finding its volume, which measures the three-dimensional space it occupies. Calculating the volume of a cylinder is a straightforward process once you know its fundamental dimensions: the radius of its base and its height.

Understanding Cylinder Volume

A cylinder is a three-dimensional geometric shape with two parallel circular bases and a curved surface connecting them. To find its "size" (volume), you need two key measurements:

  • Radius (r): The distance from the center of the circular base to its edge. If you have the diameter, simply divide it by two to get the radius.
  • Height (h): The perpendicular distance between the two circular bases.

The Formula for Cylinder Volume

The precise method for finding the volume of a cylinder involves a specific mathematical formula. As per the reference, the formula is:

Volume = π ⋅ radius² ⋅ height

This can be more concisely written as:

V = πr²h

Where:

  • V represents the Volume of the cylinder.
  • π (pi) is a mathematical constant approximately equal to 3.14 (as specified in the reference for calculation purposes).
  • r represents the radius of the cylinder's base.
  • h represents the height of the cylinder.

Step-by-Step Calculation of Cylinder Volume

To find the size (volume) of a cylinder, follow these straightforward steps:

  1. Identify the Dimensions

    Measure or identify the radius (r) of the cylinder's base and its height (h). Ensure both measurements are in the same units (e.g., centimeters, inches, meters).

  2. Write the Formula

    State the volume formula for a cylinder:
    Volume = π ⋅ radius² ⋅ height or V = πr²h.

  3. Substitute the Dimensions into the Formula

    Plug the values you identified for the radius and height into the formula. As instructed, use 3.14 as the value for $\pi$ (pi) for your calculation.

    • Example: If the radius (r) is 5 cm and the height (h) is 10 cm, the substitution would look like: V = 3.14 ⋅ (5 cm)² ⋅ 10 cm.
  4. Solve the Equation

    Perform the calculations according to the order of operations (PEMDAS/BODMAS):

    • First, square the radius ().
    • Then, multiply the squared radius by the value of $\pi$ (3.14).
    • Finally, multiply that result by the height (h).

The final answer will be in cubic units (e.g., cm³, m³, in³), which represents the three-dimensional space the cylinder occupies.

Practical Example: Calculating Cylinder Volume

Let's find the volume of a water tank that is cylindrical in shape.

Given:

  • Radius of the tank's base (r) = 2 meters
  • Height of the tank (h) = 5 meters
Step No. Action Calculation
1. Identify Dimensions r = 2 m, h = 5 m
2. Write the Formula V = πr²h
3. Substitute Values (using π = 3.14) V = 3.14 ⋅ (2 m)² ⋅ 5 m
4. Solve the Equation V = 3.14 ⋅ (4 m²) ⋅ 5 m
V = 3.14 ⋅ 20 m³
V = 62.8 m³

Therefore, the volume (or "size") of the cylindrical water tank is 62.8 cubic meters. This means the tank can hold 62.8 cubic meters of water.