Question

What is the approximate circumference of a circle with a diameter of 40 inches? (careful you need radius so 40/2)

(Use π = 3.14)

(C= 2 *π*r)


(A.) 125.6 in.


(B.) 63 in.


(C.) 251 in.

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Answer 1

(A.) 125.6 in

Explanation:

The formula of a circumference of a circle:

`C=d\pi`

d - diameter

We have d = 40in. Substitute:

`C=40\pi\ in`

`\pi\approx3.14\to C\approx(40)(3.14)=125.6\ in`

Answer 2

A. ) 125.6 in.

Explanation:

1. We are given the diameter of the circle, which is 40, and we are aware that radius=diameter÷2.
2. Therefore, the radius = (40÷2) =20.
3. The formula for the circumference of a circle is 2×pi (which in this case is 3.14) × radius, therefore:
4. 2×3.14×20 gives you your answer.
5. When you do this calculation in your head or a calculator or whatever, it equals to 125.6. Therefore A.) is the correct answer.

Hope I helped :)