circumcenter

The circumcenter of a triangle is the point of intersection of the three perpendicular bisectors of its sides. This point, often denoted O, is equidistant from the triangle's three vertices: it is the center of the unique circle passing through these three vertices, called the circumcircle of the triangle. If the triangle is right-angled, this center is the midpoint of the hypotenuse. If the triangle is acute, it lies inside the triangle; if it is obtuse, it lies outside.