This chapter starts with the properties of polygons and narrows to focus on quadrilaterals. We will study several different types of quadrilaterals: parallelograms, rhombi, rectangles, squares, kites and trapezoids. Then, we will prove that different types of quadrilaterals are parallelograms.
This chapter introduces the Polygon Sum Formula and the Regular Polygon Interior Angle Formula. After this detailed presentation of the interior angles of polygons, the next topic is exterior angles of polygons and the Exterior Angle Sum Theorem. Quadrilaterals, parallelograms, rectangles, squares, trapezoids, kites, and rhombuses are introduced and these various types of four-sided figures are classified and their properties are explored.