The formula for the circumference $C$ of a circle in terms of its radius $r$ is:

$C = 2\pi r$

To express $r$ in terms of $C$, solve for $r$:

$r = \frac{C}{2\pi}$

Thus, the formula for the radius $r$ in terms of the circumference $C$ is:

$r = \frac{C}{2\pi}$

Would you like a detailed explanation of how this formula was derived?

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Here are 5 related questions:

1. What happens to the radius if the circumference doubles?
2. How does the area of the circle relate to its circumference?
3. If the circumference is 31.4 feet, what is the radius?
4. How can you express the diameter in terms of the circumference?
5. What is the relationship between radius and area for a circle?

Tip: Remember, the diameter of a circle is always twice the radius!