The figure shows an
equilateral triangle ABC. If a point D is on the incircle, E, F,
and G are the points of tangency, DE = d,
DG = e, DF = f, and
AC = a, prove that
.
View or post a solution.

See also:
Median length, Apollonius' Theorem
Euclid's Elements Book II Proposition 13
Problem
257
Problem
256
Equilateral Triangle
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