intouch triangle

The contact triangle of a triangle Δ A B C, also called the intouch triangle, is the triangle Δ C_A C_B C_C formed by the points of tangency of the incircle of Δ A B C with Δ A B C. The contact triangle is therefore the pedal triangle of Δ A B C with respect to the incenter I of Δ A B C. It is also the Cevian triangle of Δ A B C with respect to the Gergonne point Ge and the cyclocevian triangle with respect to the same point. The contact triangle is the polar triangle of the incircle.

Adams' circle | extouch triangle | Gergonne point | pedal triangle | seven circles theorem | tangential triangle