MathDB
triangle with b+c=2a

Source: 2005 Spanish Mathematical Olympiad P6

July 20, 2018
geometryinradiuscircumradiusSides of a triangle

Problem Statement

In a triangle with sides a,b,ca, b, c the side aa is the arithmetic mean of bb and cc. Prove that: a) 0oA60o0^o \le A \le 60^o. b) The height relative to side aa is three times the inradius rr. c) The distance from the circumcenter to side aa is RrR - r, where RR is the circumradius.