Apothem
Given a Circle, the Perpendicular distance 
from the Midpoint of a Chord to the Circle'scenter is called the apothem. It is also equal to the Radius 
minus the Sagitta 
,
See also Chord, Radius, Sagitta, Sector, Segment
- Hodge Star
- Hodge's Theorem
- Hoehn's Theorem
- Hoffman-Singleton Graph
- Hoffman's Minimal Surface
- Hofstadter-Conway $10,000 Sequence
- Hofstadter Figure-Figure Sequence
- Hofstadter G-Sequence
- Hofstadter H-Sequence
- Hofstadter Male-Female Sequences
- Hofstadter Point
- Hofstadter Sequences
- Hofstadter's Q-Sequence
- Hofstadter Triangle
- Hole
- Holomorphic Function
- Holonomic Constant
- Holonomic Function
- Holonomy
- Homeoid
- Homeomorphic
- Homeomorphic Group
- Homeomorphic Type
- Homeomorphism
- Home Plate