Angle-Angle (AA), Side-Angle-Side (SAS), and Side-Side-Side (SSS).
2. Area of Polygons (Площадь многоугольников) geometriia 8 klass
Circumscribed and inscribed circles of a triangle. 5. Vectors (Векторы) - Optional/Advanced Basics: Definition of a vector, coordinates, and length. geometriia 8 klass