To determine the correct completion of the formula for finding the circumference, we can follow these steps:
1. Understand the Formula: The circumference [tex]\( C \)[/tex] of a circle is calculated using the formula:
[tex]\[
C = \pi \times \text{diameter}
\][/tex]
or alternatively,
[tex]\[
C = 2 \pi \times \text{radius}
\][/tex]
where [tex]\(\pi\)[/tex] (pi) is approximately 3.14.
2. Identify What We Need: Here, we are provided with the formula:
[tex]\[
\text{Circumference} = \pi (3.14) \times \_\_\_
\][/tex]
3. Evaluate the Given Choices:
- a. radius: This does not match the provided formula since the correct formula involving the radius is [tex]\( 2\pi \times \text{radius} \)[/tex].
- b. area: The area is not part of the formula for circumference. The area formula is [tex]\( \pi \times (\text{radius})^2 \)[/tex].
- c. diameter: The formula matches perfectly with [tex]\( \pi \times \text{diameter} \)[/tex].
- d. radius x 3: This is not a standard formula and does not fit the context of calculating circumference.
4. Conclusion: The correct completion of the given formula for finding the circumference is:
[tex]\[
\text{Circumference} = \pi \times \text{diameter}
\][/tex]
Therefore, the correct choice is:
O c. diameter
