Pappus's Harmonic Theorem
, 
, and 
in the above figure are in a Harmonic Range.
References
Coxeter, H. S. M. and Greitzer, S. L. Geometry Revisited. Washington, DC: Math. Assoc. Amer., pp. 67-68, 1967.
- Quadratic Mean
- Quadratic Reciprocity Law
- Quadratic Reciprocity Relations
- Quadratic Reciprocity Theorem
- Quadratic Recurrence
- Quadratic Residue
- Quadratic Sieve Factorization Method
- Quadratic Surd
- Quadratic Surface
- Quadratrix of Hippias
- Quadrature
- Quadrature Formulas
- Quadric
- Quadricorn
- Quadrifolium
- Quadrilateral
- Quadrillion
- Quadriplanar Coordinates
- Quadruple
- Quadruple Point
- Quadruplet
- Quadtree
- Quantic
- Quantifier
- Quantization Efficiency