1. Warm-up Homework out on desks, ready to be checked Prepare a sheet for notes, with the heading: Triangles and Quadrilaterals VOICE LEVEL ZERO

2. Triangles

3. Triangle – a figure formed by three line segments that intersect only at their endpoints

4. Pause for Polygon Family Tree Part 1

5. Angle Measure in Triangles

6. The sum of the measures of the angles in a triangle (any triangle) is 180 o.

7. Angle Measure in Triangles The sum of the measures of the angles in a triangle (any triangle) is 180 o. To find a missing measure, you: –Add the 2 measures you have –Subtract the total from 180

8. Examples P 264 (3-9)

9. Quadrilaterals

10. Quadrilateral – a polygon that has four sides and four angles

11. Pause for Polygon Family Tree Part 2

12. Angle Measure in Quadrilaterals

13. The sum of the angle measures in a quadrilateral (any quadrilateral) is 360 o.

14. Angle Measure in Quadrilaterals The sum of the angle measures in a quadrilateral (any quadrilateral) is 360 o. To find a missing measure, you: –Find the sum of the 3 measures you have –Subtract from 360

15. Examples P 274 (4-9)

16. What about other polygons?

17. 5 sides –

18. What about other polygons? 5 sides – pentagon

19. What about other polygons? 5 sides – pentagon 6 sides –

20. What about other polygons? 5 sides – pentagon 6 sides – hexagon

21. What about other polygons? 5 sides – pentagon 6 sides – hexagon 7 sides –

22. What about other polygons? 5 sides – pentagon 6 sides – hexagon 7 sides – heptagon

23. What about other polygons? 5 sides – pentagon 6 sides – hexagon 7 sides – heptagon 8 sides –

24. What about other polygons? 5 sides – pentagon 6 sides – hexagon 7 sides – heptagon 8 sides – octagon

25. What about other polygons? 5 sides – pentagon 6 sides – hexagon 7 sides – heptagon 8 sides – octagon 9 sides –

26. What about other polygons? 5 sides – pentagon 6 sides – hexagon 7 sides – heptagon 8 sides – octagon 9 sides – nonagon

27. What about other polygons? 5 sides – pentagon 6 sides – hexagon 7 sides – heptagon 8 sides – octagon 9 sides – nonagon 10 sides –

28. What about other polygons? 5 sides – pentagon 6 sides – hexagon 7 sides – heptagon 8 sides – octagon 9 sides – nonagon 10 sides – decagon

29. What about other polygons? 5 sides – pentagon 6 sides – hexagon 7 sides – heptagon 8 sides – octagon 9 sides – nonagon 10 sides – decagon 11 sides –

30. What about other polygons? 5 sides – pentagon 6 sides – hexagon 7 sides – heptagon 8 sides – octagon 9 sides – nonagon 10 sides – decagon 11 sides – undecagon

31. What about other polygons? 5 sides – pentagon 6 sides – hexagon 7 sides – heptagon 8 sides – octagon 9 sides – nonagon 10 sides – decagon 11 sides – undecagon 12 sides –

32. What about other polygons? 5 sides – pentagon 6 sides – hexagon 7 sides – heptagon 8 sides – octagon 9 sides – nonagon 10 sides – decagon 11 sides – undecagon 12 sides – dodecagon

33. What about other polygons? 5 sides – pentagon 6 sides – hexagon 7 sides – heptagon 8 sides – octagon 9 sides – nonagon 10 sides – decagon 11 sides – undecagon 12 sides – dodecagon 13 sides -

34. What about other polygons? 5 sides – pentagon 6 sides – hexagon 7 sides – heptagon 8 sides – octagon 9 sides – nonagon 10 sides – decagon 11 sides – undecagon 12 sides – dodecagon 13 sides - triskadecagon

35. Homework P 264 (10-23) P 274 (10-23) Define: –acute triangle- Trapezoid –right triangle- Parallelogram –obtuse triangle- Rectangle –scalene triangle- Rhombus –isosceles triangle- Square –equilateral triangle (all the words that are highlighted on pp 262, 263, 272, and 273 - use your textbook’s glossary)