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3.3 Sum of Interior angles of a Polygon

Figure 3.3

Figure 3.3 shows an octagon. Five diagonals can be drawn from A. This gives rise to six triangles.

Since the sum of all internal angles of a triangle is 180^{0}, the sum all the internal angles of this polygon is 6 ´ 180^{0} = 1080^{0}.

This can be generalized as :

For any n sided polygon the sum of its internal angles is ( n - 2 ) ´ 180^{0}.

Index

3. 1 Definition 3. 2 Terminology 3. 3 Sum Of Interior Angles Of A Polygon 3. 4 Sum Of Exterior Angles Of A Polygon 3. 5 Trapezoids 3. 6 Parallelogram 3. 7 Square, Rectangle And Rhombus

Chapter 4