The area of a circle is 81π m². What is the circumference, in meters? Express your answer in terms of π.

Question

The area of a circle is 81π m². What is the circumference, in meters? Express your answer in terms of π.

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Amaya 3 weeks 2021-09-28T19:05:48+00:00 2 Answers 0

Answers ( )

    0
    2021-09-28T19:07:43+00:00

    Answer:

    18\pi m

    Step-by-step explanation:

    to find the circumference we need to find the radius of the circle.

    For this, we use the formula for the area :

    a=\pi r^2

    where a is the area, \pi is a constant \pi =3.1416 and r is the radius.

    we know that the area is:

    a=81\pi m^2

    so we substitue this into the previous formula:

    81\pi m^2=\pi r^2

    and we solve for  r :

    \frac{81\pi m^2}{\pi }=r^2\\ \\81m^2=r^2\\\\\sqrt{81m^2}=r\\\\9m=r

    the radius is 9 meters.

    Now we use the formula for circumference of a circle:

    C=2 \pi r

    and substitute the value that we’ve just found for r:

    C=2\pi (9m)\\C=18\pi m

    the answer in terms of \pi is 18\pi meters is the circumference

    0
    2021-09-28T19:07:46+00:00

    Answer:

    18πm Hope this helps (: <3

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