Definition, properties of sides/angles, and signs of a parallelogram.

3. Similarity of Triangles (Подобие треугольников) Introducing the concept of "same shape, different size."

Central angles vs. Inscribed angles (and the relationship between them).

Students learn to derive and apply formulas for the space inside shapes. Squares and Rectangles ( Advanced Areas: Parallelograms ( ), Triangles ( ), and Trapezoids (

Properties of isosceles and right trapezoids; the midline of a trapezoid.