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Sum of Angles in a Polygon

What is the sum of the angles of a triangle? of a quadrilateral? of a pentagon? of a hexagon? What is the sum of the angles in convex polygons in terms of the number of sides? Move the mouse pointer over the picture for a hint.


Does the relationship for convex polygons also hold true for nonconvex polygons? Explain.

 Related External Resources

Finding the Sum of the Exterior and Interior Angles of a Polygon
This lesson uses manipulatives to discover the relationship between the sum of the angles in a polygon and its number of sides.

Sum of the Interior Angles in a Polygon

This page explains why the sum of the angles of a polygon is determined by its number of sides.

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