If a circle has a diameter of 16 feet, which expression gives its area in square feet?

A. [tex]\(8 \cdot \pi\)[/tex]

B. [tex]\(16 \cdot \pi\)[/tex]

C. [tex]\(8^2 \cdot \pi\)[/tex]

D. [tex]\(16^2 \cdot \pi\)[/tex]



Answer :

To find the area of a circle given its diameter, you can use the formula for the area of a circle:

[tex]\[ A = \pi r^2 \][/tex]

where [tex]\( r \)[/tex] is the radius of the circle.

Step-by-step:

1. Find the radius of the circle:
The diameter of the circle is 16 feet. The radius [tex]\( r \)[/tex] is half of the diameter.
[tex]\[ r = \frac{diameter}{2} = \frac{16}{2} = 8 \, \text{feet} \][/tex]

2. Substitute the radius into the area formula:
[tex]\[ A = \pi r^2 \][/tex]
[tex]\[ A = \pi (8)^2 \][/tex]

3. Calculate the expression:
[tex]\[ A = \pi \cdot 64 \][/tex]

Therefore, the expression that gives the area of the circle in square feet is:
[tex]\[ A = 64 \cdot \pi \][/tex]

Reviewing the given options:

A. [tex]\( 8 \cdot \pi \)[/tex] is not correct.
B. [tex]\( 16 \cdot \pi \)[/tex] is not correct.
C. [tex]\( 8^2 \cdot \pi \)[/tex] simplifies to [tex]\( 64 \cdot \pi \)[/tex], which is correct.
D. [tex]\( 16^2 \cdot \pi \)[/tex] is not correct.

The correct choice is:

C. [tex]\( 8^2 \cdot \pi \)[/tex]