Surface Area of Spheres Practice

Question

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Question
Find the surface area of a sphere with a diameter of 40 inches. Leave your answer in terms of pi.(1 point)
The surface area is
in.2

Answer 1

To find the surface area of a sphere, you can use the formula:

\[ \text{Surface Area} = 4\pi r^2 \]

where \( r \) is the radius of the sphere.

First, find the radius from the diameter. The diameter given is 40 inches, so the radius \( r \) is:

\[ r = \frac{\text{Diameter}}{2} = \frac{40 \text{ inches}}{2} = 20 \text{ inches} \]

Now, plug the radius into the surface area formula:

\[ \text{Surface Area} = 4\pi (20)^2 \]

Calculating \( (20)^2 \):

\[ (20)^2 = 400 \]

Now substitute back into the equation:

\[ \text{Surface Area} = 4\pi \times 400 \] \[ \text{Surface Area} = 1600\pi \]

Thus, the surface area of the sphere is:

\[ \text{Surface Area} = 1600\pi \text{ in}^2 \]

So, the surface area is \( 1600\pi \) in².