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Yr 2 w-up For 1-5 solve – you decide what to use, set up ratio, round to the hundredths place 3. 2. 1. 5 ft xo 16 cm x 32o 20 cm 17 yd 22 yd 37.690 32.360 10.64 cm 4. xo 4 ft 42o 17 m 33 cm xo 5. 15 m 22 m 20o 41 cm 42.890 15.07 cm x Problem Solving with Trigonometry Lesson 12.5 Do the following when solving trigonometry word problems… 1. Draw a picture. 2. Decide which trigonometry formula you must use. 3. Solve the word problem. SOH – CAH – TOA Right Triangle Ratios LAW OF SINES sin A sin B sin C a b c LAW OF COSINES SAS TRIANGLE AREA c a b 2ab cos C 1 A ab sin C 2 2 2 2 A large helium balloon is tethered to the ground by two taut lines. One line is 100 feet long and makes an 80° angle with the ground. The second line makes a 40° angle with the ground. How long is the second line, to the nearest foot? How far apart are the tethers? sin 40 sin 80 sin 40 sin 60 100 x 100 y x sin 40 100 sin 80 y sin 40 100 sin 60 100 sin 60 y sin 40 x 60° x = 153 ft x y = 135 ft 80° 40° y 100 sin 80 sin 40 A ship’s sonar locates a treasure chest at a 12° angle of depression. A diver is lowered 40 meters to the ocean floor. How far (to the nearest meters) does the diver need to swim along the ocean floor to get the treasure chest? 40 tan12 x x tan12 40 40 x tan 12 12° 40 m x = 188 m 12° x Farmer Joe needs to fence his triangular plot of land for his cows. The angle between two sides measures 83°. One side is 122 ft and the other is 215 ft. How much fencing does farmer Joe need to the nearest foot? What is the area of his plot of land? x 2 1222 2152 2122215cos 83 x 2 54,715.73 x 234 234 122 215 571 ft 83° 1 Area (122)(215) sin 83 2 Area = 13017 ft2 x 234 ft HOMEWORK: 12.5 Worksheet and p. 648 1, 3, 4, 6, 8