How do you calculate the radius of a circle from its circumference?

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To find the radius of a circle when you know its circumference, you can follow a straightforward mathematical approach. The relationship between the circumference (C) and the radius (r) of a circle is given by the formula:

C = 2 * π * r

Here, π (pi) is a constant approximately equal to 3.14159.

To solve for the radius, you can rearrange this formula:

r = C / (2 * π)

Now, let’s break this down step by step:

  1. Determine the Circumference: Make sure you have the value of the circumference. This can often be given in a problem or measured directly.
  2. Use the Formula: Input the circumference into the formula. For example, if the circumference is 31.42, you use:
    3. r = 31.42 / (2 * π)
  3. Calculate: Perform the division:
    4. r = 31.42 / (2 * 3.14159) ≈ 5
  4. Result: This means the radius of the circle is approximately 5 units.

This method allows you to find the radius quickly and accurately. Just remember that knowing how to manipulate these basic formulas is key to problems involving circles!

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