Interior Angles in a Regular Polygon
Use what you can see to predict how many sides the object will have
What was your prediction for each object?
What is the relationship (and ultimately the equation) between the number of sides of a regular polygon and the interior angle measure.
- Use the number of sides slider to determine the number of triangles in the polygon
- Find a rule to determine the number of triangles in a polygon with n sides
- Based on the number of triangles in each polygon, and the fact that we know each triangle’s interior angles add up to 180°. Can you predict the Sum of the Interior Angles of each polygon?
Verify:
Use the applet below to verify.
Which formula represents how to find the interior angle sum of any polygon?
What is the SUM of the angle measures in a nonagon (9 sides)?
Explain how you determined your answer without using the applet above: