Download presentation

1
Polygons Where has Polly gone?

2
Polygon A closed figure formed by joining three or more segments in a plane at their endpoints, with each line segment joining exactly 2 others. Each line segment is called a side of the polygon. This polygon has 8 sides.

3
**Circle the figures that are polygons:**

4
**Why are these NOT polygons?**

A. Open side B. Curved side C. Vertex has more than 2 segments that meet D. Curved side B C D

5
**Vertex and diagonal A vertex is where 2 sides meet.**

A diagonal joins two nonconsecutive vertices. Name the vertices and the diagonal in this polygon: Vertices: A,B,C,D,E,F Diagonal: CE

6
**List all the diagonals in this polygon:**

DB DA EC EB AC E B C D

7
**Polygons are named by the number of sides.**

8
**Name these polygons: A E B C F D A. triangle B. Quadrilateral**

C. Pentagon D. Hexagon E. Octagon F. Dodecagon E B C F D

9
**Polygons with all sides and angles equal are regular polygons**

Polygons with all sides and angles equal are regular polygons. Circle the regular polygons:

10
**Polygons are named by naming consecutive vertices in order.**

Circle all the correct names for this polygon: pentagon ABCDE pentagon AEDCB pentagon ACDBE pentagon DCBAE pentagon BDCAE pentagon BAEDC

11
**What is the sum of the angle measures in a triangle?**

Please draw a triangle on a piece of scratch paper. It can be any size or shape, just be sure it is a triangle.

12
**Now, tear off the three angles of the triangle**

Now, tear off the three angles of the triangle. Position the angles side-by-side on your desk. What shape do they make? a straight line! Draw the angles side-by-side on your paper like this ↑

13
**What is the measure of a straight line?**

180

14
**The sum of the angles of any triangle is 180°**

Find the measure of the missing angle: ے1 = (90 +35) ے1 = (125) ے1 = 55° 35° 90° ے1

15
**The sum of the angles of any triangle is 180°**

Find the measure of the missing angle: ے2 = ( ) ے2 = (130) ے2 = 50° ے2 65° 65°

16
**Find x: 3x - 4 + 5x + 10 + 6x + 6 = 180 14x + 12 = 180 -12 -12**

14x = 168 x = 12

17
**What is the sum of the angle measures in a polygon?**

We can divide the polygon into triangles, then multiply the number of triangles by 180° How many triangles make up this quadrilateral? 2 What is the sum of the angles of this quadrilateral? 2 x 180° = 360°

18
**What is the sum of the angles in this hexagon?**

720°

19
**What is the sum of the angles in this pentagon?**

3 x 180° = 540°

20
**Do you HAVE to draw the triangles to find out how many of them there are in a polygon?**

NO! 4 sides, 5 sides, sides, 2 triangles triangles triangles n sides, n-2 triangles!

21
**What is the sum of the measures of the angles of these polygons?**

180(6-2) 180(8-2) 180(10-2) = 180(4) =180(6) = 180(8) = 720° = 1080° =1440°

22
**Find the missing angle measure in this polygon:**

180(5-2) = 180(3) = 540° 540° = X 540 = X 116° = X

23
**Find the missing angle measure in this polygon:**

180(9-2) = 180(7) = 1260° 1260° = X 1260 = X 121° = X

24
**raise your achievement**

practice will raise your achievement The End

Similar presentations

OK

8-4 Angles in Polygons Problem of the Day How many different rectangles are in the figure shown? 100.

8-4 Angles in Polygons Problem of the Day How many different rectangles are in the figure shown? 100.

© 2018 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