The Geometry of Remarkable Elements

Book excerpt: This book is an English translation of a text written by Constantin Mihalescu, a retired artillery colonel and enthusiastic amateur mathematician. With the majority of the results obtained in the second half of the 19th century and the first half of the 20th century, this book was one of the most complete descriptions of geometry of its time. It contains a comprehensive collection of the most important properties of points, lines, and circles related to triangles and quadrilaterals, as they were known by the mid-1950s, and a rich assortment of problems to entice and inspire readers of all levels. Topics covered include the nine-point circle, the Simson line, the orthopolar triangles, the orthopole, the Gergonne and Nagel points, the Miquel point and circle, the Carnot circle, the Brocard points, the Lemoine point and circles, the Newton-Gauss line, and much more.