Circle

Revision as of 15:12, 29 June 2006 by DPatrick (talk | contribs) (added planar and a few links)

Definition

  • The locus of all points in a plane with distance $\displaystyle {r}$(radius) from center ${O}$
  • A cross section of a cone or cylinder parallel to the base. For more on this, see Dandelin Spheres, a commonly used method of deriving all Conic sections.
  • All x, y such that $(x - a)^{2} + (y - b)^{2} = r^{2}$ for a circle centered at $(a,b)$ with radius ${r}$

Formulas

  • Area $\displaystyle \pi r^2$
  • circumference $\displaystyle 2\pi r$

Other Properties

  • awaiting diagrams to add stuff on inscribed angles + tangents.

Practice Problems

See Also

Invalid username
Login to AoPS