This document discusses different types of angles and angle measurements: - Degrees are used to measure angles, with a protractor used to measure the size of angles. - Acute angles measure between 0 and 90 degrees. Obtuse angles measure between 90 and 180 degrees. Right angles equal 90 degrees. - Complementary angles sum to 90 degrees. Supplementary angles sum to 180 degrees. - Vertical angles are always equal in measure. - Examples are given of calculating missing angles using clues about complementary, supplementary, and vertical angles.

1. www.augusta.k12.va.us/668712831233948/lib/6687125831233948/angles.ppt Angle Measurements

2. Degrees: Measuring Angles

3. Protractor

4. Acute Angles 0 ° - 90 °

5. Acute Angles http://www.flickr.com/photos/24418961@N05/3524410992/

6. Obtuse Angles 90 ° - 180 ° Example:

7. Obtuse Angles http://www.flickr.com/photos/enlightenedfellow/1578956556/

8. Right Angles = 90 °

9. Right Angle http://www.flickr.com/photos/jefemontana/2317256019/

10. Right Angle http://www.flickr.com/photos/chrisrebouche/2763133461/ http://www.flickr.com/search/?q=%22right+angles%22&page=8

11. Complementary Angles Two angles that sum to 90 degrees. Example: 58 + 32 = 90

12. Complementary Angles http://www.flickr.com/photos/fap_portfolio/3578730712/ http://www.flickr.com/photos/escher1/3476297278/

13. Supplementary Angles Example: 139 + 41 = 180

14. Supplementary Angles http://www.flickr.com/photos/svyates/2415340942/

15. Vertical Angles … are EQUAL 110 110 70 70

16. Vertical Angles http://www.flickr.com/photos/gwilmore/39689162/

17. Review State whether the following are acute, right, or obtuse. 1. 2. 3. 4. 5.

18. Complementary and Supplementary 1. Two angles are complementary. One measures 65 degrees. 2. Two angles are supplementary. One measures 140 degrees. Find the missing angle.

19. Complementary and Supplementary Find the missing angle. You do not have a protractor. Use the clues in the pictures. 1. 2. x 55 165 x

20. Vertical Angles Find the missing angle. You do not have a protractor. Use the clues in the pictures. 58 x X=58

21. More drawings 20 C J D E F G H 70 90 70 20 90

22. Final Drawing ? B A F E D C 60 G ? 68 ? ?