Rodrigues's Curvature Formula
where
is the unit Normal Vector and 
is one of the two Principal Curvatures.See also Normal Vector, Principal Curvatures- Trigonometry Values Pi/3
- Cycle (Circle)
- Cycle Graph
- Cycle (Map)
- Cycle (Permutation)
- Cyclic Graph
- Cyclic Group
- Cyclic Hexagon
- Cyclic-Inscriptable Quadrilateral
- Cyclic Number
- Cyclic Pentagon
- Cyclic Permutation
- Cyclic Polygon
- Cyclic Quadrangle
- Cyclic Quadrilateral
- Cyclic Redundancy Check
- Cyclid
- Cyclide
- Cyclidic Coordinates
- Cycloid
- Cycloid Evolute
- Cycloid Involute
- Cycloid Radial Curve
- Cyclomatic Number
- Cyclotomic Equation