Step 2: Circumference Equation.
Take your pick, you will get the same answer with each equation (if you don't, well then maybe you should just try coloring inside of the circles instead of trying to find their circumference.)
Circumference= Two x Pi x r
Circumference is equal to two multiplied by Pi multiplied by the radius of the circle.
Now, do you have the memory of a goldfish (I think their memory is only 3 seconds. Or maybe it was 2, or maybe it was 4? I don't remember). Here is an easy way to remember the circumference equation:
TWO PIES ARE BETTER THAN ONE
2 Pi r