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§ 5-7. Law of Sines. Goals. Solve triangle by using law of sines . Determine if a triangle has 0, 1, or 2 solutions. LAW OF SINES. When the measures of two sides of a triangle and the measure of angle opposite one of them are given, there may not always be one solution!.
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§ 5-7 Law of Sines
Goals • Solve triangle by using law of sines. • Determine if a triangle has 0, 1, or 2 solutions
When the measures of two sides of a triangle and the measure of angle opposite one of them are given, there may not always be one solution!
One of the following will be true: • 1. No triangle exists • 2.Exactly one triangle exists • 3.Two triangles exist.
Case #1 • When mA < 90º • If a = b sin A one solution exists • If a > b sin A and a ≥ b one solution exists • If a < b sin A no solutions exist • If b sin A < a < b two solution exists
Case #2 • When mA≥ 90º • If a ≤ b no solutions exist • If a > b one solution exists
Example #1 • Solve ∆ ABC if A = 32º14´, B= 57º40´, and c = 14.3 m. • C= • a= • b=
Example #2 • Solve ∆ ABC if A = 58º, b=14 cm, and a =10 cm.
Example #3 • Solve ∆ ABC if A= 72º14´ , b= 22 in, and a = 21 in. Round to the nearest minute and tenth.
Example #4 • Solve ∆ ABC if A = 105º, b=55, and a =73
Assignment • Page 324-326 • #’s 11-32 even, 46 • Due Monday