6

Part of 1972 Spain Mathematical Olympiad

Problems(1)

inradii of triangle by touchpoints of 3 ext. tangent circles 1972 Spanish P6

Source:

Given three circumferences of radii

r

r'

r''

, each tangent externally to the other two, calculate the radius of the circle inscribed in the triangle whose vertices are their three centers.

geometryradiustangent circles