Sections Activity – Observing the Relationship among the Angles of a Polygon Sum of Interior Angles of a Polygon (Angle Sum Theorem) Number of Degrees or the Measure of one Interior Angle of a Regular Polygon Number of Degrees or Measure of One Exterior Angle of a Polygon Activity – Observing the Relationship among the Angles of a Polygon Sum of Interior Angles of a Polygon (Angle Sum Theorem) Number of Degrees or the Measure of one Interior Angle of a Regular Polygon Number of Degrees or Measure of One Exterior Angle of a Polygon Print Share Developing Algebraic Expressions to Represent Geometric Properties of Angle Relationships in Polygons Copy and paste the link code above.