CalcElfCalcElf › Circle of radius 7 cm: its circumference
Circle of radius 7 cm: its circumference
A circle has a radius of 7 cm. Find the circumference of this circle.
Answer
Circumference 43.98
Step-by-step
- 2 × π × 7 = 43.98Circumference = 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 7 cm as if it were the diameter.
- Using 3.14 × 7 × 7, which is the area formula.