Читать книгу Geometry for Students and Parents - Sergey D Skudaev - Страница 8

A line drawn from a vertex of a triangle that divides the angle of origin into two equal angles is called the angle bisector. See figure 6. Each point on an angle bisector is equidistant from the sides of the angle.

The bisectors of a triangle are concurrent. A point of their intercept is called the incenter. The incenter is equidistant from all sides of the triangle and is the center of the inscribed circle. See figure 15.

Figure 15. An incenter of a triangle with an inscribed circle.