Circumference of a Circle Calculator
This Circumference of a Circle Calculator helps you find the distance around a circle when the radius is known. It uses the formula C = 2πr, where r is the radius and the answer is written in units. Multiply the radius by 2π to get the circumference. It is a simple way to check answers, understand the circle circumference formula, and practise basic geometry step by step.
In the diagram, the radius is labeled r.
Step-by-step method
- Identify what is given.
- Write the formula.
- Substitute the value and calculate the circumference.
Formula:
Example 1: r = 5
Step 1 - Identify what is given.
In this problem: The given radius is r = 5.
Step 2 - Write the formula.
In this problem: Use the circumference formula: C = 2πr.
Step 3 - Substitute the value and calculate the circumference.
In this problem: Substitute r = 5: C = 2π × 5 = 31.41592654.
Final answer: C = 31.41592654
Example 2: r = 3.5
Step 1 - Identify what is given.
In this problem: The given radius is r = 3.5.
Step 2 - Write the formula.
In this problem: Use the circumference formula: C = 2πr.
Step 3 - Substitute the value and calculate the circumference.
In this problem: Substitute r = 3.5: C = 2π × 3.5 = 21.99114858.
Final answer: C = 21.99114858
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