The diameter of a circle can be found using different formulas depending on the information you have:
- If you know the radius rrr, the diameter ddd is:
d=2rd=2rd=2r
The diameter is twice the length of the radius.
- If you know the circumference ccc, the diameter is:
d=cπd=\frac{c}{\pi}d=πc
where π≈3.14159\pi \approx 3.14159π≈3.14159.
- If you know the area AAA, first find the radius:
r=Aπr=\sqrt{\frac{A}{\pi}}r=πA
then find the diameter as:
d=2r=2Aπd=2r=2\sqrt{\frac{A}{\pi}}d=2r=2πA
In summary, the diameter is either twice the radius, or the circumference divided by π\pi π, or twice the square root of the area divided by π\pi π depending on the given data.
