If sin θ = 3/5 and θ is acute, what is cos θ?
Answer and explanation
Correct answer: A. 4/5
- Step 1: sin²θ + cos²θ = 1. Step 2. cos²θ = 1 − 9/25 = 16/25, so cos θ = 4/5. Answer: 4/5. Why not the others: 3/4 is tan θ and 5/4 is the reciprocal of the cosine of a different angle.
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