butterfly theorem

Let M be the midpointMathworldPlanetmathPlanetmathPlanetmath of a chord PQ of a circle, through which two other chords AB and CD are drawn. If AD intersects PQ at X and CB intersects PQ at Y,then M is also the midpoint of XY.

The theorem gets its name from the shape of the figure, which resembles a butterfly.

Title butterfly theoremMathworldPlanetmath
Canonical name ButterflyTheorem
Date of creation 2013-03-22 13:10:06
Last modified on 2013-03-22 13:10:06
Owner giri (919)
Last modified by giri (919)
Numerical id 8
Author giri (919)
Entry type Theorem
Classification msc 51-00