EXPLORING THE EXTERIOR ANGLES OF A POLYGON

Purpose: Below is a link to a Java Sketchpad Applet which allos students to explore the properties of the interior angles of a polygon. By changing the dimensions of a quadrilateral, pentagon, hexagon, etc., the students will come to the conclusion that the sum of the measures of the interior angles of a polygon is alwasy 180(n-2) where n represents the number of sides of the polygon. This is an important task for the students to complete according to the Mathematics Curriculum Framework for Massachusetts, which says that in grades 9-10 students should "analyze characteristics and properties of two- and three-dimensional geometric shapes and develop mathematical arguments about geometric relationships" which is the purpose of this activity.