This manual is an addition to the textbook "Geometry, 7-9" by L. S. Atanasyan, V. F. Butuzov and others. (M.: Enlightenment, 1990 and subsequent editions). It is fully consistent with the program of in-depth study of mathematics. The book can also be used in classes of educational institutions for individual work with students showing interest in mathematics, in elective classes and in the work of a mathematics circle.