The figure below shows a triangle ABC with the circumradius R, the inradius r and the exradii ra, rb, rc. Prove that \(r_a+r_b+r_c=4 \cdot R+r\) .
This step-by-step interactive illustration was created with GeoGebra.
GeoGebra is free and multi-platform dynamic mathematics software for all levels of education that joins geometry, algebra, tables, graphing, statistics and calculus application, intended for teachers and students. Many parts of GeoGebra have been ported to HTML5.
Ten problems: 1411-1420
Inradius, Incenter, Incircle
Exradius, Excenter, Excircle
Circle Tangent Line
HTML5 and Dynamic Geometry
View or Post a solution