How do you find the radius of a circle when the circumference is already given?

Question

I don't remember how do do this, so any help would do. Thanks. :)...

Answer 1

circumference = 2 * pi * radius

Divide by 2*pi, and you get:

radius = circumference / (2 * pi)

So, if the circumference is given, divide that number by 2*pi, and you'll have the radius.

Answer 2

First of all, the formula for circumference of a circle is 2πr.
When you want to calculate the radius, you will set up an equation like this: Example) (Suppose the circumference of the circle is 16) 2πr=16. Then, divide both sides by 2π.
You are now left with r=16/2π
Plug it into calculator and there's your answer.

Answer 3

Circumference = 2 * Pi * radius

So, if you have the circumference, divide it by 2 * Pi (or about 6.28318). The answer will be the radius.

Answer 4

the formula for circumference is Circumference= 2 times Pi times radius. take that formula and manipulate it. divide 2 times pi by 2 times pi to get rid of it. what u do to one side u do to the other so divide Circumference by 2pi. now formula looks like this. Circumference divided by 2 pi = r . flip it to perform equation. r = Circumference divided by 2 times pi.
do equation!

example.

if circumference equals 88cm:

r = circumference divided by 2 times pi.
= 88 divided by (3.14 times 2)
r = 552.64cm

Answer 5

Circumference = 2 x pi x r
r = C/ (2 pi)

Answer 6

you set up an equestion.
circumferance=diamiter x pi, or diamiter times approximatly 3.1415926
so the radius would be circumference divided by 3.1415926,
this gives you the diamiter. and because diamiter is twice the radius you just divide that by 2.

Example:cercumference = 31.415926 divided by pi (3.14926) =10. 10 is your diamiter, which divided by 2 gives you your radius.
radius=5 units

Answer 7

circumference = 2 PI r
so r = circumference / (2 PI)

Answer 8

divide it by 2.

Answer 9

circum = 2*PI*radius

radius = cicum/2PI