Skip to content Skip to navigation

Connexions

You are here: Home » Content » An Angle Summary

Navigation

Content Actions
  • Download module PDF
  • Add to ...
    Add the module to:
    • My Favorites
    • A lens
    • An external social bookmarking service
    • My Favorites (What is 'My Favorites'?)
      'My Favorites' is a special kind of lens which you can use to bookmark modules and collections directly in Connexions. 'My Favorites' can only be seen by you, and collections saved in 'My Favorites' can remember the last module you were on. You need a Connexions account to use 'My Favorites'.
    • A lens (What is a lens?)

      Definition of a lens

      Lenses

      A lens is a custom view of Connexions content. You can think of it as a fancy kind of list that will let you see Connexions through the eyes of organizations and people you trust.

      What is in a lens?

      Lens makers point to Connexions materials (modules and collections), creating a guide that includes their own comments and descriptive tags about the content.

      Who can create a lens?

      Any individual Connexions member, a community, or a respected organization.

    • External bookmarks
  • E-mail the author

Recently Viewed

This feature requires Javascript to be enabled.

An Angle Summary

Module by: Interactive Mathematics Program

Intent

In this activity, students reflect on and apply their knowledge of the relationship of sides and angles in polygons. This activity emphasizes the important mathematical relationships they have worked on recently, including the unproven fact that the sum of the angles in a triangle is 180° and, based on this conjecture, the proven polygon angle sum formula.

Mathematics

This activity draws upon the polygon angle sum formula to introduce the concept of a regular polygon, a polygon in which all angles have the same measure and all sides are the same length. Students draw and measure angles using a protractor one more time.

Progression

This activity serves as a wrap-up for the angle and polygon investigation sequence. After recalling and writing about what they know about polygon angles, students solve the angle measures of a regular pentagon and regular octagon and then draw these polygons.

Approximate Time

20 minutes for activity (at home or in class)

10 minutes for discussion

Classroom Organization

Individuals, followed by small groups

Materials

Protractors

Doing the Activity

This activity requires little or no introduction.

Discussing and Debriefing the Activity

You may want to have one or two volunteers read or present their work on Question 1 and then allow the class to add to or to correct the material presented.

Be sure to get some explanations for the angle sum formula. These might refer, for example, to the idea of dividing a polygon into triangles or to the numerical pattern found in Polygon Angles.

For Question 2, ask students to explain their work. Use the opportunity to briefly emphasize the definition and basic properties of a regular polygon. Then ask what difficulties students had in drawing the polygons.

In Question 3, students are asked once more to use protractors to draw polygons, reinforcing their grasp of the pattern developed in the previous activities. If they correctly determine the size of each angle in a regular polygon, and measure correctly, their figures should close—that is, the last side of each figure should meet the first side at the final vertex.

Comments, questions, feedback, criticisms?

Send feedback