1. 8.4 Trigonometry- Part I Then: You used the Pythagorean Theorem to find missing lengths in right triangles. Now: 1. Find trigonometric ratios using right triangles. 2. Use trigonometric ratios to find angle measures in right triangles. http://www.akaritutoring.com/subjects/clipart/trigonometry-clip-art.gif

2. Trigonometry * To measure a triangle Trigonometric ratio: ratio of the lengths of two sides of a right triangle. Use in real world to indirectly measure tall heights worhttp://tarantamath.pbworks.com/f/1338559331/8-5%20real%20world.pngld

3. Trigonometric Ratios

6. Memorizing Trig Functions http://edtech2.boisestate.edu/millerl/images/SohCahToa.jpg http://www.nztutor.co.nz/moodle/pluginfile.php/741/mod_lesson/page_contents/483/ SOH%20CAH%20TOA%201.png

7. Example 1a: Find Sine, Cosines, and Tangent Ratios Find the sin L, cos L, tan L, sin N, cos N, tan N. Express each ration as a fraction in simplest terms, and as a decimal to the nearest hundredth. sin L = _______ = ________ cos L = _______ = ________ tan L = _______ = ________

8. Example 1: Find Sine, Cosines, and Tangent Ratios Express each ration as a fraction in simplest terms, and as a decimal to the nearest hundredth. sin N = _______ = ________ cos N = _______ = ________ tan N = _______ = ________

9. Example 1b: Find the sin A, cos A, tan A, sin B, cos B, tan B Express each ration as a fraction in simplest terms, and as a decimal to the nearest hundredth. sin A = _______ = ________ cos A = _______ = ________ tan A = _______ = ________ sin B = _______ = ________ cos B = _______ = ________ tan B = _______ = ________

10. Example 2: Using Special Right Triangles a. Use a special right triangle to express the cosine of 60° as a fraction and as a decimal to the nearest hundredth. http://www.biology.arizona.edu/biomath/tutorials/trigonometric/graphics/trig_30_60 _90.gif

11. Example 2: b. Use a special right triangle to express the cosine of 45° as a fraction and as a decimal to the nearest hundredth. http://www.biology.arizona.edu/biomath/tutorials/trigonometric/graphics/trig _45_45_90.gif

12. Example 3: Estimating Measures Using Trigonometry Find x. Round to the nearest hundredth. a.

13. Example 3: Estimating Measures Using Trigonometry b. c.

14. Example 3d: Estimating Measures Using Trigonometry EXERCISING A fitness trainer sets the incline on a treadmill to 7°. The walking surface is 5 feet long. Approximately how many inches did the trainer raise the end of the treadmill from the floor?

15. 8.4 Part I Assignment: Page 573-574 #16-19, 20-28 evens, 29-35