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Find the circumference of a circle whose area is 60pi cm^2.

A.

2 √(15\pi ) \: cm
B.

4 √(15\pi) \: cm
C.

30\pi \: cm
D.

900\pi \: cm


1 Answer

3 votes

Answer:

none of the offered choices is correct


circumference=4\pi√(15)\,\text{cm}

Explanation:

We can use the area equation to find the radius of the circle, then use that to find the circumference.

A = πr²

60π = πr²

60 = r² . . . . . . . divide by π

√60 = 2√15 = r . . . . take the square root

Now, the circumference is given by ...

C = 2πr

C = 2π(2√15) = 4π√15 . . . . cm

_____

If the area were 60 cm², answer choice B would be correct. Since it is 60π cm², no answer choice is correct.

User Khandad Niazi
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