Lesson 9.1 Right Triangle Trigonometry (Day 2) Learning Goal: (G-SRT.C.8 - Pre-requisite Skill) I can evaluate trigonometric functions of acute angles. I can find unknown side lengths and angle measures of right triangles. Essential Question: How can you find a trigonometric function of an acute angle θ? Homework Discussion 5 in 5 mi 8.6 km 14.1 mi 2 yd 6. km 7. m 8. yd 9. yes 10. yes 11. no 12. no 13. yes 14. yes

Special Right Triangles Know These 45°-45°-90° 30°-60°-90° 1 45° 1 2 30° 60° sin 45° = sin 30° = =

Finding an Unknown Side Length Find the value of x for the right triangle. Ex 1: 12 Ex 2: 60° x

Solving a Triangle: finding the unknown side lengths and angle measures of a triangle. Use technology. Ex 1: Solve △ABC. c 34° b=13 a Ex 2: Solve △ABC.

Group Consensus 1. Find the value of x for the right triangle shown. Solve △ABC using the diagram and 
the given measurements. 2. B = 45°, c = 5 3. A = 32°, b = 10 4. A = 71°, c = 20 5. B = 60°, a = 7

Solving Real-Life Problems You are hiking near a canyon. While standing at A, you measure an angle of 90º between B and C, as shown. You then walk to B and measure an angle of 76° between A and C. The distance between A and B is about 2 miles. How wide is the canyon between A and C?

Example: A parasailer is attached to a boat with a rope 72 feet long. The angle of elevation from the boat to the parasailer is 28°. Estimate the parasailer’s height above the boat.

Practice to Strengthen Understanding Exit Question: What does the standard deviation tell us about a data distribution? Practice to Strengthen Understanding Hmwk #32 Big Ideas p466 #21-26, 27-45 odd