👉 In geometry, an excircle of a triangle is a circle that touches (is tangent to) one of the sides of the triangle at just one point. The other two points of tangency are called the excenters. An excircle is named after its center which is known as the excircle center or excentral center. It's also often denoted by an uppercase letter, such as E in the context of triangles. In a triangle ABC, the excenter at point A is defined as
