Question

Cones, Cylinders, & Spheres Unit Test
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Question
The surface area of a sphere is 7.84π ft.2
What is the radius of this sphere?

Answer 1

To find the radius of a sphere given its surface area, you can use the formula for the surface area of a sphere:

\[
SA = 4\pi r^2
\]

Where \(SA\) is the surface area and \(r\) is the radius.

Given that the surface area of the sphere is \(7.84\pi\) ft², you can set up the equation:

\[
4\pi r^2 = 7.84\pi
\]

To simplify, you can divide both sides of the equation by \(\pi\):

\[
4r^2 = 7.84
\]

Next, divide both sides by 4:

\[
r^2 = \frac{7.84}{4} = 1.96
\]

Now, take the square root of both sides to find \(r\):

\[
r = \sqrt{1.96} = 1.4
\]

Thus, the radius of the sphere is \(1.4\) ft.