Find the circumference of a circle whose radius is $9\text{cm}$. Give your answer in centimeters.

Step-by-step solution

1. Write the formula for circumference: $C=2\pi r$.
2. Substitute $r=9\text{cm}$ into the formula: $C=2\pi \times 9$.
3. Simplify: $C=18\pi \text{cm}$.
4. Use $\pi \approx 3.14$ to obtain the numerical value: $C\approx 18\times 3.14=56.52\text{cm}$.

Concept tested: circumference

Published 25 August 2026 · How this solution was prepared and checked

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