Shapes & Designs

Angle Sum


In this investigation, you will explore the sum of the measures of the interior angles of triangles, quadrilaterals and other polygons using rotations of 180° about a midpoint of a side.

After you complete the activity, try another shape. Do your results stay the same? Explain.

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© 2006 Applet written by S. Keller, Department of Mathematics, Michigan State University

© 2006 Connected Mathematics Project, Michigan State University and Pearson
Education, Inc. publishing as Pearson Prentice Hall