CalcElfCalcElf › Circle of radius 5 cm: find the circumference
Circle of radius 5 cm: find the circumference
A circle has a radius of 5 cm. Find the circumference of this circle.
Answer
Circumference 31.42
Step-by-step
- 2 × π × 5 = 31.42Circumference = 2πr
Why it works
The circumference of a circle is its diameter times pi, and the diameter is twice the radius.
Common mistakes
- Treating the radius 5 cm as if it were the diameter.
- Using 3.14 × 5 × 5, which is the area formula.