What is the circumference of a circle with diameter 5 inches?

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Answer 1 · 2017-05-10T20:52:44

$C = 5pi ~~ 15.708$ inches (3 dp)

The circumference of a circle is given by:

$C = 2pir$

Where $r$ is the radius, or equivalently

$C = pid$

Where $d=2r$ is the diameter.

So, if the diameter is 5 inches then the circumference is:

$C = 5pi ~~ 15.708$ inches (3 dp)

Answer 2 · 2017-05-10T21:18:08

Exact circumference = $2pi2.5$ in.

The formula for the circumference of a circle is:

$C=2pir$ ,

where $C$ is circumference, $pi$ is 3.1415..., and $r$ is the radius.

$r=d/2$ , where $d$ is diameter.

Calculate the diameter.

$r=(5color(white)(.)"in")/2$

$r=2.5color(white)(.)"in"$

Calculate circumference.

$C=2pir$

$C=2xxpixx2.5color(white)(.)"inches"$ or $2pi2.5color(white)(.)"inches"$ $lArr$ This is the exact circumference.

$C=2xxpixx2.5"in"~~15.7color(white)(.)"in"$ $lArr$ This is an approximate circumference because it is rounded off.