The circumference of a circle can be found using either the radius or the diameter of the circle with the value of Pi (π). The two main formulas are:
- Circumference C=2πrC=2\pi rC=2πr, where rrr is the radius of the circle.
- Circumference C=πdC=\pi dC=πd, where ddd is the diameter of the circle (and d=2rd=2rd=2r).
Pi (π) is a mathematical constant approximated as 3.14159 or often taken as 3.14 for easier calculations. To find the circumference:
- If you know the radius, multiply it by 2 and then by π: C=2×π×rC=2\times \pi \times rC=2×π×r.
- If you know the diameter, multiply it directly by π: C=π×dC=\pi \times dC=π×d.
Example: For a radius of 25 units,
C=2×π×25=2×3.14×25=157 units.C=2\times \pi \times 25=2\times 3.14\times 25=157\text{ units}.C=2×π×25=2×3.14×25=157 units.
Therefore, the circumference is the distance around the circle, calculated using one of these formulas depending on what measurement is known.
