Sum of interior angles of a Regular Polygon

1. Use the slider to change the number of side.[br]2. Observe the Sum of interior angles and measure of individual angle below slider.

What do you mean by Interior angle?

Which formula represents how to find the interior angle sum of any polygon?

(number of sides + 2) x 180 number of sides x 180 (number of sides - 2) x 180 number of sides x 360

What is the SUM of the angle measures in a nonagon (9 sides)?

900° 1080° 1440° 1260°

What is the SUM of the angle measures in a triangle (3 sides)?

90 180 120 30

Information: Sum of interior angles of a Regular Polygon