Given triangle Δ A B C, there are four lines simultaneously tangent to the incircle (with center I) and the A-excircle (with center J_A). Of these, three correspond to the sidelines of the triangle, and the fourth is known as the A-intangent, illustrated above. The intangents intersect one another pairwise, and their points of intersection form the so-called intangents triangle.

circle-circle tangents | extangent | intangents circle | intangents triangle