What is the radius of a circle with a circumference of 28 pi?

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Answer 1 · 2018-05-09T17:21:22

The radius is $14$ $14$ units.

Start by finding the diameter; the formula for circumference is $π d$ $pid$ , so set up an equality:

$28 π$ $28pi$ = $c$ $c$
$28 π$ $28pi$ = $π d$ $pid$

Divide both sides by $π$ $pi$ :

$\frac{28 π}{π} = \frac{π d}{π}$ $(28pi)/(pi)=(pid)/(pi)$

$(28color(red)(cancel(pi)))/(color(red)(cancel(pi)))$ = $(color(red)(cancel(pi))d)/(color(red)(cancel(pi)))$

$28=d$

Diameter is twice as large as radius, so divide your diameter by 2 to get radius.

$d/2=r=28/2=color(red)(14)$

Therefore, your radius is $14$ units.