1. Interior and Exterior Angles of Triangles

2. Right Angle A right angle has a measurement of 90 degrees

3. Straight Angle A straight angle Has a measurement Of 180 degrees

4. Acute Angle An acute angle has A measurement of Less than 90 degrees

5. Obtuse Angle An obtuse angle has A measurement of More than 90 degrees

6. Complimentary Angles Their measures add up to exactly 90 degrees

7. Supplementary Angles Their measures add up to exactly 180 degrees

8. Finding Missing Angles 25º x x + 25 = 90

9. 45ºx x + 45 = 180

10. Finding the complimentary and supplementary angles 30° Complimentary: 30 + x = 90 Supplementary: 30 + x = 180 The complimentary angle is 60⁰ and the supplementary angle is 150⁰

11. 65° The complimentary angle is ___⁰ and the supplementary angle is _____⁰

12. 105° In this case there is no complimentary angle, only a supplementary angle. Why?

13. Triangles

14. Finding a Missing Angle The sum of all angles in a triangle is 180 degrees. You should remember that from last year, but why?

15. Let’s Look at it Three Ways Cutting off the angles 1 2 3 1 2 3 I cut off angles 2 and 3 and lined them up to form a straight line

16. Rotating the Triangle 1 2 3 1 2 3 3 1 2 In this picture angles 1, 2, and 3 combine to make a straight line of 180⁰

17. Using parallel lines and transversals 1 2 3 231 Angle 2 by vertical angles, angles 1 and 3 by complimentary angles

18. Putting it into action

19. Your Turn

20. Finding an exterior angle -Create a straight line to solve 80⁰ + x⁰ make up the straight line. The 55⁰ and 45⁰ have nothing to do with it.

21. Your Turn 35° 55°

22. 60º x

23. 145º x y

24. Find all the missing angles 85° 154°

25. Closure Two angles that are supplementary add up to ______

26. Closure Two angles that are complimentary add up to ______

27. Closure A straight line is _______

28. Closure The sum of all angles in a triangle equals:

29. Closure: With a partner find all the missing angles 125° 168°