MathDB
R,Area,r in arithmetic progression

Source:

October 31, 2019
geometrycircumcircleinradiusarithmetic sequence

Problem Statement

Prove that the sum of the squares of the medians of a triangle is at least 9/4 9/4 if the circumradius of the triangle, the area of the triangle and the inradius of the triangle (in this order) are in arithmetic progression.
Dumitru Crăciun