Question

what is the formula for the circumference of a circle?
〇 $c = pi r^2$
〇 $c = 2pi r$
〇 $c = 2pi r^2$
〇 $c = pi r^3$
done

Explanation:

The circumference of a circle is calculated using the formula that relates the radius $r$ (or diameter, since diameter $d=2r$) to the constant $\pi$. The options $\pi r^2$ and $2\pi r^2$ are area formulas, and $\pi r^3$ has no relation to circle circumference. The correct formula is $C=2\pi r$.

Answer:

B. $C = 2\pi r$