Volume of cylinders

In the earlier lesson, you learned that the volume of the rectangular prism is found by multiplying the area of the base by the height of the prism. Mathematicians commonly write this as

V = B • h

Finding the volume of a cylinder is the exact same formula!

  Step 1: Find the area of the base

  Step 2: Multiply it by the height

In other words:

Volume = (Area of base) • height

Volume = (Area of a circle) • height

Volume = (π • r • r) • h

Movie goes here

Example 1

This cylinder has a radius of 4 cm and a height of 10 cm. Find its volume.

V = B • h

V = (π • r • r) • h

V = (3.14 • 4 • 4) • 10

V = 502.4 cm^3

Example 2

This cylinder has a diameter of 6 cm and a height of 9 cm. What is its volume?

First we need to find the radius, so we divide the diameter by 2.

Radius = 6 ÷ 2 = 3 cm

V = B • h

V = (π • r • r) • h

V = (3.14 • 3 • 3) • 9

V = 254.34 cm^3

Try this GeoGebra applet:

Move the hint slider to 0 to hide the hints and solution. Create a cylinder and then find the volume. Use the slider to check your answer.

Sorry, the GeoGebra Applet could not be started. Please make sure that Java 1.4.2 (or later) is installed and active in your browser (Click here to install Java now)

Duane Habecker, Created with GeoGebra