Adding It All Up
In this lesson, students draw various polygons and investigate their interior angles. The investigation is done using both an interactive tool and paper and pencil to foster an understanding of how different patterns can lead to the same solution. After comparing results with a partner, students develop a formula showing the relationship between the number of sides of a polygon and the sum of the interior angles.
Math Makes a Connection: Exploring Angle Sums
In this interactive game, students will explore the sum of the measures of the interior angles of triangles, quadrilaterals, and other polygons using rotations of 180 degrees about a midpoint of a side. This game is part of the Connected Math site.