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.