Question

How do i find the circumference of a circle? If I use a 3 as an estimate of pie and the circle is 10 mm across

Answer 1

If you're using pie it would be

2*$\pi$*5 because the radius is half of the diameter.

But since you're using three it's

2*3*5

If it helps remember: Twinkle twinkle little star, circumference equals 2 pi r