Geometry Problems, Online Education

Problem 524: Circle, Equilateral Triangles, Midpoint, Side, Measurement. Level: High School, SAT Prep, College geometry

The figure shows an equilateral triangle ABC (side a) inscribed in a circle C1. The point D is the midpoint of BC and E and F are on the circle C1. If the triangle DEF is equilateral (side x), prove that Formula to prove. Post a comment or solution.

Circle with equilateral triangles

Reference: Fukagawa Hidetoshi, Tony Rothman, "Sacred Mathematics: Japanese Temple Geometry" (Princenton University Press, 2008).



See also:

Circle, Tangent, Diameter, Radius, Congruence

Problem 525.
Circles, Diameter, Tangent, Radius, Congruence, Measurement.

Tangent Circles

Problem 523.
Tangent Circles, Diameter Perpendicular, Collinearity.

Geometry Problem: Right triangle, Circle, Tangent

Problem 522.
Right Triangle, Circle, Diameter, Tangent.

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