Use Trig with Right Triangles (Section 13-1 Alg 2)
θ Trig ratios are used in right triangles. Two angles other than right angles are called reference angles.
θ Opposite Leg Hypotenuse Adjacent Leg Hypotenuse across from Right angle Opposite Leg across from Reference Angle Adjacent Leg next to Reference Angle
θ Opp sin θ = Hyp
θ Adj cos θ = Hyp
θ Opp tan θ = Adj
θ Hyp csc θ = cosecant=reciprocal of sin Opp
θ Hyp sec θ = secant=reciprocal of cos Adj
θ Adj cot θ = cotangent=reciprocal of tan Opp
Write each ratio. Example 1: 3 sin θ = 5 4 cos θ = 5 3 θ tan θ = 4
Write each ratio. Example 1: 5 csc θ = 3 5 sec θ = 4 4 θ cot θ = 3
Write each ratio. Example 2: 12 sin θ = 13 θ 5 cos θ = 13 12 tan θ = 5
Write each ratio. Example 2: 13 csc θ = 12 θ 13 sec θ = 5 5 cot θ = 12
Write each ratio. Example 3: 6 sin θ = 10 θ 8 cos θ = 10 6 tan θ = 8
Write each ratio. Example 3: 10 csc θ = 6 θ 10 sec θ = 8 8 cot θ = 6
Write each ratio. Example 4: 12 sin θ = 15 θ 9 cos θ = 15 12 tan θ = 9
Write each ratio. Example 4: 15 csc θ = 12 θ 15 sec θ = 9 9 cot θ = 12
SOH CAH TOA ‘s CHO SHA CAO
HW #1 Practice 13-1 (1-6)
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HW # 2 Practice 13-1 (7-14)