1. Write each fraction as a decimal rounded to the nearest hundredth. 1. 2. Solve each equation. 3. 4. 0.670.29 x = 7.25x = 7.99

2. Chapter 9: Right Triangle Trigonometry 9-2: Sine and Cosine Ratios

3. Find the sine and use to find side lengths in right triangles and to solve real-world problems. Objectives

4. A trigonometric ratio is a ratio (fraction) of two sides of a right triangle.

5. Holt Geometry 8-2 Trigonometric Ratios

6. Holt Geometry 8-2 Trigonometric Ratios In trigonometry, the letter of the vertex of the angle is often used to represent the measure of that angle. For example, the sine of  A is written as sin A. Writing Math

7. Holt Geometry 8-2 Trigonometric Ratios Example 1A: Finding Trigonometric Ratios Write the trigonometric ratio as a fraction and as a decimal rounded to the nearest hundredth. sin J

8. Holt Geometry 8-2 Trigonometric Ratios Check It Out! Example 1c Write the trigonometric ratio as a fraction and as a decimal rounded to the nearest hundredth. sin B

9. Holt Geometry 8-2 Trigonometric Ratios Example 3A: Calculating Trigonometric Ratios Use your calculator to find the trigonometric ratio. Round to the nearest hundredth. sin 52° sin 52°  0.79 Be sure your calculator is in degree mode, not radian mode. Caution!

10. Holt Geometry 8-2 Trigonometric Ratios Check It Out! Example 3b Use your calculator to find the trigonometric ratio. Round to the nearest hundredth. sin 62° sin 62°  0.88

11. Holt Geometry 8-2 Trigonometric Ratios Example 4B: Using Trigonometric Ratios to Find Lengths Find the length. Round to the nearest hundredth. QR is opposite to the given angle, P. You are given PR, which is the hypotenuse. Since the opposite side and hypotenuse are involved, use a sine ratio.

12. Holt Geometry 8-2 Trigonometric Ratios Example 4B Continued Write a trigonometric ratio. Substitute the given values. 12.9(sin 63°) = QR 11.49 cm  QR Multiply both sides by 12.9. Simplify the expression.

13. Holt Geometry 8-2 Trigonometric Ratios Check It Out! Example 4a Find the length. Round to the nearest hundredth. DF is the hypotenuse. You are given EF, which is opposite to the given angle, D. Since the opposite side and hypotenuse are involved, use a sine ratio.

14. Holt Geometry 8-2 Trigonometric Ratios Check It Out! Example 4a Continued Write a trigonometric ratio. Substitute the given values. Multiply both sides by DF and divide by sin 51°. Simplify the expression. DF  21.87 cm

15. Holt Geometry 8-2 Trigonometric Ratios Check It Out! Example 4d Find the length. Round to the nearest hundredth. JL is the opposite side to the given angle, K. You are given KL, which is the hypotenuse. Since the opposite side and hypotenuse are involved, use a sine ratio.

16. Holt Geometry 8-2 Trigonometric Ratios Check It Out! Example 4d Continued Write a trigonometric ratio. Substitute the given values. Multiply both sides by 13.6. Simplify the expression. JL = 13.6(sin 27°) JL  6.17 cm

17. Pg. 479 #1 – 3, (just find sin M) 4, 7, 8, 9