Antipedal Triangle
The antipedal triangle 
of a given Triangle 
is the Triangle of which is the PedalTriangle. For a Triangle with Trilinear Coordinates 
and Angles ,
, and 
, the antipedal triangle has Vertices with Trilinear Coordinates
The Isogonal Conjugate of the Antipedal Triangle of a given Triangle is Homothetic withthe original Triangle. Furthermore, the Product of their Areas equals theSquare of the Area of the original Triangle (Gallatly 1913).See also Pedal Triangle
References
Gallatly, W. The Modern Geometry of the Triangle, 2nd ed. London: Hodgson, pp. 56-58, 1913.
- Spieker Circle
- Spigot Algorithm
- Spijker's Lemma
- Spindle Cyclide
- Spindle Torus
- Spinode
- Spinor
- Spiral
- Spiral Point
- Spira Mirabilis
- Spiric Section
- Spirograph
- Spirolateral
- Spline
- Splitting
- Splitting Algorithm
- Sponge
- Sporadic Group
- Sports
- Sprague-Grundy Function
- Sprague-Grundy Number
- Sprague-Grundy Value
- Spread (Link)
- Spread (Tree)
- Spun Knot