1. Formulas involving Polygons
Lesson 7.3

2. Sums of interior angles

3. Theorem 55: Sum Si of the measure of the angles of a polygon with n sides is given by the formula
Si = (n-2)180

4. Exterior angles 1 5 2 4 3

5. Theorem 57: The number of diagonals that can be drawn in a polygon of n sides is given by the formula d = n(n-3) 2
Try: draw then do the math!

6. Quadrilateral
360 = 360

7. Hexagon: 720 int. = 2(360) ext. 720 = (n-2)(180) 720 = 180n – 360
Hexagon: 720 int. = 2(360) ext.
720 = (n-2)(180)
720 = 180n – 360
1080 = 180n
n = 6