6. Let’s analyze this polygon! consecutive sides consecutive vertices consecutive angles Quadrilateral ABCD 1) What is this polygon’s name? 2) How many sides and vertices are there? 4 sides & 4 vertices 3) Name all of my sides using proper notation. AB, BC, CD, and DA 4) Name all of my angles using proper notation. <ADC, < DCB, < CBA, <BAD 5) Identify my consecutive sides. 6) Identify my consecutive vertices. 7) Identify my consecutive angles. _ _ _ _
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10. Classifying Polygons In your notes, create this chart to act as a guide to naming polygons. Make sure you include space for the drawings. Draw each polygon with the correct number of sides. Then, find the number of diagonals up to the 6-sided polygon. Try the others as a challenge!! Polygon Name # of Sides # of Diagonals Drawing Triangle 3 Quadrilateral 4 5 6 7 8 9 10 Undecagon 11 Dodecagon 12 n
11. Polygons An Australian 50-cent coin is a dodecagon! The UK 50-pence coin is a heptagon! Don’t forget to draw the polygons! Polygon Name # of Sides # of Diagonals Triangle 3 0 Quadrilateral 4 2 Pentagon 5 5 Hexagon 6 9 Heptagon 7 14 Octagon 8 20 Nonagon 9 27 Decagon 10 35 Undecagon 11 44 Dodecagon 12 54 n -gon n ½n(n–3)
Remind students that we saw vertex last week during our angles lesson!
Perform this slide together as a class by compiling the polygon’s names on the board.
Allow students to work independently to find four different ways that this polygon can be named. Then, gather class together to compile list.
Emphasize the use of pre-fixes to denote the number of sides in the polygon.
Have students create this chart in their notebook. Have students start by drawing each polygon. Then, have them figure out the number of diagonals by connecting non-consecutive vertices. (up to hexagon – have them do the others as a challenge). Discuss the n-gon and what it represents!
![AIM 1.4 : How can we define and classify polygons with 3 to 12 sides? ,[object Object],[object Object],[object Object],[object Object],[object Object],REMINDER! Quiz #1 on MONDAY ! September 9 th , 2009](https://image.slidesharecdn.com/geo1-4-polygonslesson-090903213040-phpapp01/85/Geo1-4-Polygons-Lesson-1-320.jpg)
![Polygons ,[object Object],[object Object],Polygons: NOT Polygons:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)