Introduction to Trigonometry and Law of Sines and Cosines

Identify the Law of Sines

• Sin²x + Cos²x =1

• Sin(A)/a = Sin(B)/b = Sin(C)/c

• Sin(A)Sin(B)Sin(C) = 1

• Soh-Cah-Toa

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Use the Law of Cosines to find the measure of angle x. The side lengths shown are 25, 32 and 37. <x is opposite the 25 length side.

• 38.5^o

• 41.7^o

• 45.1^o

• 51.3^o

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What is the length of side x? x is opposite a 28 degree angle. 14 cm is the side length given.

• 6.57 cm

• 7.05 cm

• 7.44 cm

• 8.33 cm

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Find angle Z

• 18.77°

• 71.23°

• 51.06°

• 57.71°

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Which Law would you use?

• Law of Sines

• Law of Cosines

• Law of the Jungle

• Law of Gravity

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Calculate the length of AC

• 32.68 ft

• 110.70 ft

• 27.54 ft

• 26.58 ft

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Solve triangle ABC if A=40°, B=20°, a=2

• C=120°, b=1.06, c=2.69

• C=120°, b= 2.69, c=1.06

• C= 120°, b=2.68. c=3.26

• C=120°, b=3.26 c=2.68

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In ΔABC, B = 45^o, a = 28 and b = 27. Find all possible values for Angle A

• 47.2° only

• 47.2° and 132.8°

• 47.2° and 87.8°

• 47.2° and 137.2°

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If three sides of a triangle are given, the Law of ____ is used to solve the triangle.

• Cosines

• Sines

• Tangents

• Cosecants

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Find the missing side.

• 15.9 in.

• 22.8 in.

• 6.54 in.

• 521.1 in.

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