A Triangle with two equal sides (and two equal Angles). The name derives from the Greek *iso* (same)
and *skelos* (Leg). The height of the above isosceles triangle can be found from the Pythagorean Theorem as

(1) |

(2) |

There is a surprisingly simple relationship between the Area and Vertex Angle . As shown in the
above diagram, simple Trigonometry gives

(3) | |||

(4) |

so the Area is

(5) |

No set of points in the Plane can determine only Isosceles Triangles.

© 1996-9

1999-05-26