Orthocenter

The orthocenter of a triangle, usually written H, is the point where the triangle three altitudes, extended if needed, all meet. Where this point sits depends on the shape of the triangle: in an acute triangle it falls inside the triangle, in a right triangle it sits exactly on the vertex of the right angle, and in an equilateral triangle it lands on the same point as the centroid and every other triangle center. Because its position changes so directly with the triangle own shape, the orthocenter is one of the basic reference points used when studying a triangle other properties and centers.