# Table of Contents

Definition of the inscribed circle of a triangle

The theorem on the inscribed circle of a triangle

Properties of the inscribed circle’s center of a triangle

The inscribed circle’s radius. Formulas

The area of a triangle in terms of the inscribed circle’s radius

The distance between the inscribed circle’s center and the point of intersection of the medians

Property of the inscribed circle’s and a straight line

The distance from the vertex to the inscribed circle’s center. Formulas

Formulas for the circumscribed circle’s radius and the inscribed circle’s radius. Euler’s inequality

A circle inscribed into an orthotriangle