Question 728741: Describe how to find the area of a circle when given only the circumference of the circle. Found 2 solutions by ohtheirony, Edwin McCravy:Answer by ohtheirony(35) (Show Source):
You can put this solution on YOUR website! To find the circumference of a circle, use pi times the diameter (2 radius), and the area of a circle is pi times . If we work backwards, we divide the circumference by pi to give us the diameter. The diameter is twice the radius, so we divide the diameter by two. Now, we put the radius into pi times the radius squared () to find the area.
It's better to get the formula for A in terms of C, which
amounts to the rule:
"Square the circumference and divide by 4p"
The formulas are:
C = 2pr
A = prē
We solve the circumference equation for r:
C = 2pr
= r
Substitute that for r in the area formula
A =
A =
A =
A =
A =
Square the circumference and divide by 4p,
Edwin
