IXL | Volume of spheres

Volume of spheres

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What is a

sphere?

A sphere is a three-dimensional object shaped like a ball. In a sphere, every point on the surface is an equal distance from the center.

The radius of a sphere, r, is the distance from the center of the sphere to any point on its surface.

You can find the volume of a sphere using this formula.

𝜋

Let's try it! Find the volume of this sphere. Use 3.14 as an approximation for 𝜋

Since you're using an approximation for 𝜋

use ≈ to mean "approximately equal to."

𝜋

216

288

𝜋

≈

288

3.14

≈

904.32

So, the volume of the sphere is approximately 904.32 cubic centimeters!

Another example

Let's try another example. This time you know the diameter. Remember that the diameter is twice the radius. Find the volume of the sphere. Use 3.14 as an approximation for 𝜋

In this example, the diameter is given. You can find the radius by dividing the diameter by 2.

So, the radius is 3.

𝜋

≈

3.14

≈

113.04

So, the volume of the sphere is approximately 113.04 cubic inches!

Fun Fact

Compared to any other shape, spheres have the largest volume for the smallest surface area. Bubbles are spherical because they shrink to the smallest shape for the volume of air inside. Balloons do the same thing! A sphere allows for maximal volume with minimal surface area.