What is the circumference of the circle whose area is 25pi ?

Expert Answers

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The area of a circle is given as pi*r^2.

Here the area is 25*pi

pi*r^2 = 25*pi

=> r = sqrt 25

=> r = 5

Now the circumference of a circle is 2*pi*r = 2*pi*5 = 10*pi.

The required circumference is 10pi or 31.42 units.

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Given the area of the circle is 25pi.

But, we know that the formula of the area of a circle is given by:

A = r^2 * pi

We will substitute:

==> A = r^2 * pi = 25*pi

We will divide by pi.

==> r^2 = 25

==> r= 5

Then, the radius of the circle is r= 5.

Now we will calculate the circumference.

We know that:

C = 2*r*pi  

==> C = 2* 5 * pi  = 10pi = 31.42 ( approx.)

Then, the circumference of the circle is 10pi = 31.42 units ( approx.)

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