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Back to Prove and use Pythagorean identity — Problem 2 · Task Set 78

Exercises: Pythagorean Identity: Proof and Applications

Grade 9·21 problems·~35 min·Common Core Math - HS Functions·group·hsf-tf-c-8
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Fluency Practice

1.

Given sin⁡θ=−513\sin\theta = -\dfrac{5}{13} and θ\theta is in Quadrant III,
use the Pythagorean identity to find cos⁡θ\cos\theta. Express your answer
as a fraction in simplest form.