What is the approximate length of the radius, r? Use 3.14 for π. Round to the nearest inch.
+30 Well, that isn't enough information to do anything with. I'm going to assume that there's a circle and that you are given a circumference.
formula for circumference:
C = 2πr
We can rearrange it to solve for the radius in terms of the circumference (by dividing both sides by 2π):
r = C / (2π)
And if you're using 3.14 for pi, then you would obviously substitute that in:
r = C / 6.28
They might have given you the area of the circle instead of the circumference.
formula for area of a circle:
A = πr2
Same thing as before; rearrange the equation, solving for r.
r2 = A / π
r = sqrt(A / π)
