What is the formula for the circumference of a circle?

Conditions

• Applies to Euclidean circles.
• $r$ is the radius of the circle.

Reasoning, step by step

1. Identify the radius $r$ of the circle.
2. Multiply the radius by $2\pi$.
3. The result is the exact circumference $P$.

Example

The formula '=2πr' appears next to a circle, and the speaker says 'P is equal to 2 pi r'.

Common misconceptions

• Confusing the circumference formula with the area formula ($A = \pi r^2$).
• Assuming the formula applies to non-Euclidean geometries without modification.

Watch the explanation

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