Question

What is the area of a circle with a diameter of 10 millimeters? Estimate the area to the tenths place using 3.14 for π.(1 point)
Responses

15.7 square mm
15.7 square mm

78.5 square mm
78.5 square mm

314 square mm
314 square mm

79 square mm

Answer 1

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

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

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

Given that the diameter of the circle is 10 millimeters, the radius \( r \) would be:

\[
r = \frac{\text{diameter}}{2} = \frac{10 \text{ mm}}{2} = 5 \text{ mm}
\]

Now, substitute \( r \) into the area formula using \( \pi \approx 3.14 \):

\[
\text{Area} = 3.14 \times (5 \text{ mm})^2
\]
\[
= 3.14 \times 25 \text{ mm}^2
\]
\[
= 78.5 \text{ mm}^2
\]

Therefore, the area of the circle is **78.5 square mm**.

The correct response is:

**78.5 square mm**.