What is the circumference of a circle with an area of 49p in2?

24.5p inches

14p inches

7p inches

3.5p inches

Is "p" supposed to be "pi"? Or is it just a variable in general? If you mean "pi", then since A = pi * r^2, setting this equal to 49 pi gives you r = 7. Use this and the circumference formula (C = 2 * pi * r) to get the circumference.

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3 Responses to “What is the circumference of a circle with an area of 49p in2?”

Geezah on November 5th, 2009 at 10:55 pm

Is "p" supposed to be "pi"? Or is it just a variable in general? If you mean "pi", then since A = pi * r^2, setting this equal to 49 pi gives you r = 7. Use this and the circumference formula (C = 2 * pi * r) to get the circumference.
References :
masterliang123 on November 5th, 2009 at 11:40 pm

Area = p * r^2
49p = r^2
r = 7

Circumference = 2pr = 2 * p * 7 = 14p

Answer B is correct.
References :
First L on November 6th, 2009 at 12:21 am

area = Pi (r^2) = 49p
I assume p is an arbitrary number not necessarily = Pi

r^2 = 49p/Pi
r = sqrt (49p/Pi)

Perimeter = 2Pi r
Perimeter = 2Pi (sqrt(49p/Pi)
let’s use Pi = 3.14
we get
Perimeter = 2*3.14 sqrt(49p/3.14) =
6.28 sqrt (15.605p) = 6.28*3.95 sqrt(p)= 24.8 sqrt(p)
References :

Area List