Hi 3DST3!
The diameter of a circle is x 2 the radius. The radius is, as you checked, 5m. Therefore the answer cannot be A.
The circumference formulas are
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* diameter or 2
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(3.14 rounded)r. The radius of the circle is 5 and pi (
rounded) = 3.14, therefore, 2*3.14*5. 2*3.14*5 = 31.4. Therefore b isn't a correct answer choice and neither is e.
The diameter, as I said, is 2 * r. Our r is 5. 2 * 5 = 10. 10 is our diameter and C the correct answer choice.
The area of a circle's formula is
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
Therefore 3.14 * 5^2 -> 3.14 * 25 = 78.5. D is correct.
Answers that are correct:
C
D
F
Answers that are incorrect:
A
B
E