Elearn Geometry Problem 222: Viviani Theorem, Exterior point

Equilateral Triangle, Exterior Point
For a given point D outside an equilateral triangle ABC, the sum of the distances DE and DF minus DG from the point D to the sides BC, AB and AC respectively is equal to the altitude of the triangle.



See complete Problem 222 at:
gogeometry.com/problem/p222_viviani_theorem_equilateral_triangle_exterior.htm

Level: High School, SAT Prep, College geometry