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13-5: Sine and Cosine Ratios. Essential Question: SOH-CAH-TOA?. 13-5: Sine and Cosine Ratios. Sine (Sin) : Opposite Leg/ Hypotenuse Cosine (Cos) : Adjacent Leg/ Hypotenuse Example: Find sin A, cos A, sin B, and cos B sin A = opposite / hypotenuse = 4 / 5
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13-5: Sine and Cosine Ratios Essential Question: SOH-CAH-TOA?
13-5: Sine and Cosine Ratios • Sine (Sin): Opposite Leg/Hypotenuse • Cosine (Cos): Adjacent Leg/Hypotenuse • Example: Find sin A, cos A, sin B, and cos B • sin A = opposite/hypotenuse = 4/5 • cos A = adjacent/hypotenuse = 3/5 • sin B = opposite/hypotenuse = 3/5 • cos B = adjacent/hypotenuse = 4/5
13-5: Sine and Cosine Ratios • Your Turn • Find each value • sin P • sin R • cos P • cos R 12/13 5/13 5/13 12/13
13-5: Sine and Cosine Ratios • A ski run 8395 feet long has a 20˚ angle of elevation. What is the vertical drop from the top of the run? • Looking for theangle opposite 20˚ • Given the hypotenuse • Use the sin function • sin 20 = x/8395 • 8395 sin 20 = x • 2871.3 ft = x
13-5: Sine and Cosine Ratios • You can use the sin-1 and cos-1 buttons on your calculator to find the measure of unknown angles, like we did yesterday with the tan-1 button. • Example: Find the measure of H to the nearest degree. • We have the adjacent side (8) • We have the hypotenuse (9) • Use the cosine function • cos x = 8/9 • cos-1 (8/9) = x • 27˚ = x
13-5: Sine and Cosine Ratios • YOUR TURN • Find the measure of Rto the nearest degree • 71˚
13-5: Sine and Cosine Ratios • Assignment • Worksheet #13-5 • Thursday Chapter 13 Preview • Friday Chapter 13 Review • Next Monday Chapter 13 Test • Next Tuesday Quarterly Preview • Next Wed/Thur Quarterly Review • Next Friday 3rd Quarterly Exam