1. Lesson 5.2 Polygon Exterior Angle Sum HOMEWORK: 5.2/ 1-10

2. 2 Polygon Exterior Angle Sum Theorem The sum of the measures of the exterior angles of any polygon, one at each vertex is 360. m ∠1 + m∠2 + m∠3 + m∠4 + m∠5 = 360

3. Exterior angle sum = 360° If and Only if

4. Example: How many sides does a polygon have if it has an exterior  measure of 36°. = 36 360 = 36n 10 = n

5. Example: Find the sum of the interior  s of a polygon if it has one exterior  measure of 24. = 24 n = 15 S = (n - 2)180 = (15 – 2)180 = (13)180 = 2340

6. Find x. Example Using exterior angle sum: Sum of the known exterior angles = 305 ° Exterior angle sum – 305 ° x = 360° – 305° = 55°

7. Example How many sides does each regular polygon have if its exterior angle is: a. 120  b. 24  360 120 Ext sum One angle 360 24 3 sides triangle 15 sides = 3 = 15

8. Exterior Angles ONLINE! http://www.mathopenref.com/polygonexterio rangles.html http://www.mathopenref.com/polygonexterio rangles.html https://www.khanacademy.org/math/geomet ry/parallel-and-perpendicular- lines/triang_prop_tut/v/sum-of-the-exterior- angles-of-convex-polygon https://www.khanacademy.org/math/geomet ry/parallel-and-perpendicular- lines/triang_prop_tut/v/sum-of-the-exterior- angles-of-convex-polygon