Download presentation

1
NAMING POLYGONS

2
**What does the word “polygon” mean?**

Let's Discuss What does the word “polygon” mean? What is the smallest number of sides a polygon can have? What is the largest number of sides a polygon can have?

3
Triangle Octagon Quadrilateral Nonagon Pentagon Decagon Dodecagon Hexagon n-gon Heptagon

4
**Hip Bone’s connected to the… Classifying Polygons**

Polygons with 3 sides… Triangles Polygons with 4 sides… Quadrilaterals Polygons with 5 sides.. Pentagons But wait we have more polygons Polygons with 6 sides… Hexagons Polygons with 7 sides… Heptagons Polygons with 8 sides… Octagons But still we have more polygons Polygons with 9 sides… Nonagons Polygons with 10 sides… Decagons Polygons with 12 sides… Dodecagons And now we have our polygons

5
**Important Terms A VERTEX is the point of intersection of two sides F A**

CONSECUTIVE VERTICES are two endpoints of any side. F A B C D E A segment whose endpoints are two nonconsecutive vertices is called a DIAGONAL. Sides that share a vertex are called CONSECUTIVE SIDES.

6
**More Important Terms EQUILATERAL - All sides are congruent**

EQUIANGULAR - All angles are congruent REGULAR - All sides and angles are congruent

7
**Polygons are named by listing its vertices consecutively.**

F E D

8
**Polygons can be CONCAVE or CONVEX**

9
**Ex. 3 Classify each polygon as convex or concave.**

10
Diagonals & Angle Measures

11
**What is the sum of the measures of the interior angles of a triangle?**

REVIEW: What is the sum of the measures of the interior angles of a triangle? 180° 180° 180° What is the sum of the measures of the interior angles of any quadrilateral? 360°

12
**Sum of measures of interior angles**

# of triangles Sum of measures of interior angles # of sides 1(180) = 180 3 1 2(180) = 360 4 2 3 3(180) = 540 5 6 4 4(180) = 720 n-2 (n-2) 180 n

13
**If a convex polygon has n sides, then the sum of the measure of the interior angles is (n – 2)(180°)**

14
**Ex. 1 Use the regular pentagon to answer the questions.**

Find the sum of the measures of the interior angles. Find the measure of ONE interior angle 540° 108°

15
**Two more important terms**

Interior Angles Exterior Angles

16
1 2 3 4 5 If any convex polygon, the sum of the measures of the exterior angles, one at each vertex, is 360°.

17
**If any convex polygon, the sum of the measures of the exterior angles, one at each vertex, is 360°.**

1 3 2

18
**If any convex polygon, the sum of the measures of the exterior angles, one at each vertex, is 360°.**

1 2 4 3

19
**Ex. 2 Find the measure of ONE exterior angle of a regular hexagon.**

60°

20
**Ex. 3 Find the measure of ONE exterior angle of a regular heptagon.**

51.4°

21
**Ex. 4 Each exterior angle of a polygon is 18**

Ex. 4 Each exterior angle of a polygon is 18. How many sides does it have? n = 20

22
Ex. 5 The sum of the measures of five interior angles of a hexagon is What is the measure of the sixth angle? 185°

23
Ex. 6 The measure of the exterior angle of a quadrilateral are x, 3x, 5x, and 3x. Find the measure of each angle. 30°, 90°, 150°, and 90°

24
Ex. 7 If each interior angle of a regular polygon is 150, then how many sides does the polygon have? n = 12

25
Practice Time Practice Worksheet 10-2

26
Homework: Page 406 # even Page 411 # 8-18 all

27
**Foldable for Formulas Sum of INTERIOR Angles ONE INTERIOR Angle Sum**

EXTERIOR Angles ONE EXTERIOR Angle

Similar presentations

© 2021 SlidePlayer.com Inc.

All rights reserved.

To make this website work, we log user data and share it with processors. To use this website, you must agree to our Privacy Policy, including cookie policy.

Ads by Google