Explore the world of polygonal shapes in this 20-minute educational video from the Elementary Mathematics series. Delve into the fundamental concepts of geometry, including triangles, rectangles, parallelograms, and pentagons. Learn about regular polygons, different types of quadrilaterals, and various triangle classifications. Discover the properties of isosceles triangles and engage in exercises to identify and count different types of triangles. Gain a solid foundation in geometric shapes that have been studied for thousands of years, emphasizing the importance of incorporating geometry alongside arithmetic in early mathematics education.