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

Question

.(1 point)
Responses

314 square mm
314 square mm

78.5 square mm
78.5 square mm

79 square mm
79 square mm

15.7 square mm

Answer 1

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

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

where \( r \) is the radius.

1. First, we need to find the radius. The diameter is given as 10 millimeters, so the radius is half of that:

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

2. Now, substitute the radius into the area formula. Using \( \pi \approx 3.14 \):

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

Thus, the area of the circle is approximately 78.5 square mm.

So the correct response is 78.5 square mm.