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
𝜋
A. 314
B. 78.8
C.15.7
D. 79
𝜋
A. 314
B. 78.8
C.15.7
D. 79
Answers
GPT-4o mini
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 diameter is given as 10 millimeters, so the radius \( r \) is half of that:
\[
r = \frac{10}{2} = 5 \text{ millimeters}
\]
Now, using \( \pi \approx 3.14 \):
\[
\text{Area} = 3.14 \times (5)^2
\]
Calculating \( (5)^2 \):
\[
(5)^2 = 25
\]
Now substituting this back into the area formula:
\[
\text{Area} = 3.14 \times 25
\]
Calculating it:
\[
3.14 \times 25 = 78.5
\]
Rounding this to the tenths place, we get 78.5, which is approximately 78.8.
Thus, the closest answer choice for the area of the circle is:
**B. 78.8**
\[
\text{Area} = \pi r^2
\]
where \( r \) is the radius of the circle. The diameter is given as 10 millimeters, so the radius \( r \) is half of that:
\[
r = \frac{10}{2} = 5 \text{ millimeters}
\]
Now, using \( \pi \approx 3.14 \):
\[
\text{Area} = 3.14 \times (5)^2
\]
Calculating \( (5)^2 \):
\[
(5)^2 = 25
\]
Now substituting this back into the area formula:
\[
\text{Area} = 3.14 \times 25
\]
Calculating it:
\[
3.14 \times 25 = 78.5
\]
Rounding this to the tenths place, we get 78.5, which is approximately 78.8.
Thus, the closest answer choice for the area of the circle is:
**B. 78.8**