Question

The formula for the circumference of a circle is C = 2r. What is one-fourth of the circumference of a circle that measures 12 centimeters around? If necessary, use 3.14 for .

Answer 1

The formula of a circumference is:

`C=2\pi r`

r - radius

or

`C=d\pi`

d - diameter

We have d = 12cm. Substitute:

`C=12\pi\ cm`

One-fourth of the circumference:

`(1)/(4)C=(1)/(4)\cdot12\pi=3\pi\ cm\approx3\cdot3.14=9.42\ cm`

Answer: 9.42 cm.