# Dynamic Geometry 1468: Steiner's Theorem, Triangle, Circumradius, Inradius,
Sum of Exradii, Step-by-step
Illustration

The figure below shows a triangle ABC with
the circumradius R, the inradius r and the exradii r_{a}, r_{b}, r_{c}.
Prove that \(r_a+r_b+r_c=4 \cdot R+r\) .

See solution below

## Static Diagram of Geometry 1468: Steiner's Theorem

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