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:

$\dfrac{1}{4}C=\dfrac{1}{4}\cdot12\pi=3\pi\ cm\approx3\cdot3.14=9.42\ cm$

Answer:  9.42 cm.