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. The radius is half of the diameter.
Given a diameter of 10 millimeters, the radius \( r \) is:
\[ r = \frac{10 \text{ mm}}{2} = 5 \text{ mm} \]
Now, we can calculate the area using \( \pi \approx 3.14 \):
\[ \text{Area} = 3.14 \times (5 \text{ mm})^2 \] \[ \text{Area} = 3.14 \times 25 \text{ mm}^2 \] \[ \text{Area} = 78.5 \text{ square mm} \]
So, the area of the circle is 78.5 square mm.
The correct response is 78.5 square mm.