Line segment and its length. Convex and concave angle. Acute, right, obtuse, stright, reflex and full angle. Vertical, adjacent, complementary and supplementary angles. Corresponding angles. Alternate angles. Intercept (Thales') theorem. Axis of symmetry of figure. Axis of symmetry of line segment. Point of symmetry. Circle. Circle and its area. Circumference and area of a circle. Arc, sector and segment of a circle. Relative position of a straight line and a circle. Angles in circle. Inscribed angles subtend the same arc. Inscribed angle theorem. Tangent-chord theorem. Tangent-secant theorem. Circle circumscribed about a triangle. Circle inscribed in a triangle. Circle circumscribed about a quadrilateral. Circle inscribed in a quadrilateral. Relative position of two circles. Triangle Sum of angles in a triangle. Triangle inequality. Altitude of a triangle. Median of a triangle. Symetralna. Angle bisector. Angle bisector theorem. Isosceles triangle. Equilateral triangle. Right Triangle. Pythagorean theorem. Area of a triangle. Congruent Triangles. Similar triangles. The law of cosines. The law of sines. Quadrilateral and other polygons. Sum of angles in a quadrangle. Square. Rectangle. Parallelogram. Rhombus. Trapezoid. Kite. Polygons. Regular pentagon. Regular hexagon. Perimeter of a polygon. Congruent polygons. Similar polygons. Proofs and transformations. Homothety. Isometric transformation. Reflection symmetry. Point symmetry. Rotation.