Page 113 - TB_6B

Challenge Sum of the Interior Angles of a Polygon

Find the relationship between the number of triangles in a polygon and
the sum of its interior angles.

Draw lines from one vertex to divide the polygons into triangles as shown
below.

Count the number of triangles in each polygon and complete the table.

Polygon Quadrilateral Pentagon Hexagon
Number of Line(s) Drawn

Number of Triangles

How many triangles are there in a polygon with n number of sides?

Discuss the relationship between the number of triangles in a polygon and
the sum of its interior angles.

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