Fagnano's Theorem
If 
and 
are two points on an Ellipse
 | (1) |
and 
such that | (2) |
and 
. Then | (3) |
 | (4) |
is an incomplete Elliptic Integral of the Second Kind, 
is a complete Elliptic Integralof the Second Kind, and 
is a Jacobi Elliptic Function. If 
and 
coincide, the point where they coincide is called Fagnano's Point.- Cartan Torsion Coefficient
- Cartesian Coordinates
- Cartesian Ovals
- Cartesian Product
- Cartesian Trident
- Cartography
- Cascade
- Casey's Theorem
- Casimir Operator
- Cassini Ellipses
- Cassini Ovals
- Cassini Projection
- Cassini's Identity
- Cassini Surface
- Castillon's Problem
- Casting Out Nines
- Catacaustic
- Catalan Integrals
- Catalan Number
- Catalan's Conjecture
- Catalan's Constant
- Catalan's Diophantine Problem
- Catalan Solid
- Catalan's Problem
- Catalan's Surface