Circle
Circle Formulas
(See representation above)
r : radius
d : diameter
P : perimeter
A : area
Circle diameter formulas
| Diameter given radius (r) : `d = 2*r` |
Other formulas :
given perimeter (P) : `d = P/pi`
given area (A) : `d = 2*sqrt(A/pi)`
Circle perimeter formulas
| Perimeter given radius (r) : `P = 2*pi*r` |
Other formulas :
given diameter (d) : `P = pi*d`
given area (A) : `P = 2*sqrt(pi*A)`
Circle area formulas
| Area given radius (r) : `A = pi*r^2` |
Other formulas :
given diameter (d) : `A = pi*d^2/4`
given perimeter (P) : `A = P^2/(4*pi)`
Circle radius formulas
| Radius given perimeter (P) : `r = P/(2*pi)` |
Other formulas :
given diameter (d) : `r = d / 2`
given area (A) : `r = sqrt(A/pi)`
See also
Plane Geometry calculators
Geometry calculators
Mathematics calculators