The pedal coordinates of a point 
with respect to the curve 
and the pedal point 
are the radial distance 
from 
to 
and the perpendicular distance
from 
to the line 
tangent to 
at 
.
Pedal Coordinates
See also
Pedal Curve, Pedal PointExplore with Wolfram|Alpha
References
Lawrence, J. D. A Catalog of Special Plane Curves. New York: Dover, pp. 2-3, 1972.Yates, R. C. "Pedal Equations." A Handbook on Curves and Their Properties. Ann Arbor, MI: J. W. Edwards, pp. 166-169, 1952.Referenced on Wolfram|Alpha
Pedal CoordinatesCite this as:
Weisstein, Eric W. "Pedal Coordinates." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/PedalCoordinates.html