Algebra 2: Law of Learning Target: By the end of today’s lesson we will be able to successfully use trigonometry to solve triangles. The trigonometric ratios that we have learned can be used to find angle measures (sine–1, cos–1, tan–1) and sides lengths (sin, cos, tan) in __________ triangles. The Law of Sines and Law of Cosines can be used to find angle measures and side lengths in ________ triangle. Law of Sines: If has sides of length and as shown then: a, b, c ΔABC Use when given an and the side ANGLE OPPOSITE!!! (Note: Set up a proportion that relates the sine of two angles and their opposite sides!) Ex 1: Use the Law of Sines to solve the triangle. Round answer to the nearest tenth. Ex 2: Two people are walking toward each other on a path through the park. The path runs east and west. A hot air balloon is directly above the path between them. One of the walkers, a female, sees the balloon when looking east at an angle of elevation of . The other walker, a male, sees the balloon looking west at an angle of elevation of . If the walkers are yards apart, how far is the balloon from the male observer? Honors Geometry 9-7: Law of Cosines
Algebra 2: Law of Learning Target: By the end of today’s lesson we will be able to successfully use trigonometry to solve triangles. The trigonometric ratios that we have learned can be used to find angle measures (sine–1, cos–1, tan–1) and sides lengths (sin, cos, tan) in __________ triangles. The Law of Sines and Law of Cosines can be used to find angle measures and side lengths in ________ triangle. Law of Sines: If ΔABC has sides of length a, b, and c as shown then: Use when given an ANGLE and the side OPPOSITE!!! (Note: Set up a proportion that relates the sine of two angles and their opposite sides!) Ex 1: Use the Law of Sines to solve the triangle. Round answer to the nearest tenth. Ex 2: Two people are walking toward each other on a path through the park. The path runs east and west. A hot air balloon is directly above the path between them. One of the walkers, a female, sees the balloon when looking east at an angle of elevation of . The other walker, a male, sees the balloon looking west at an angle of elevation of . If the walkers are yards apart, how far is the balloon from the male observer? Honors Geometry 9-7: Law of Cosines
alg_2_law_of_sines_and_law_of_cosines.docx