The surface area of a sphere with a diameter of 40 inches is
. The calculation involves finding the radius, applying the formula
, resulting in an exact expression in terms of

To find the surface area of a sphere, we use the formula
, where r is the radius. Since the diameter is given, we can find the radius by dividing the diameter by 2.
Given a diameter of 40 inches, the radius (r) is 40/2 = 20 inches. Now substitute this value into the formula:
![\[ A = 4\pi (20)^2 \]](https://img.qammunity.org/2024/formulas/mathematics/high-school/tuecb51pfh1nky2r8ah3thdi4ys3f24tag.png)
Simplifying,
![\[ A = 4\pi * 400 \]](https://img.qammunity.org/2024/formulas/mathematics/high-school/fys03weos78mi0jbirz06pm2vza11ro9hi.png)
![\[ A = 1600\pi \]](https://img.qammunity.org/2024/formulas/mathematics/high-school/d4lf8ojtmlx8otwpxurdv0djskpvnjscrr.png)
Therefore, the surface area of the sphere is
. This is the exact expression in terms of
since the value of
is irrational, and leaving it in this form provides a more accurate representation of the surface area.