If sin(θ) = − 2/3 with θ in Quadrant III, what is cos(θ)?

Answer 1

sin(θ) = -2/3

sin²(θ) + cos(θ)² = 1

cos(θ) = √1 - sin²(θ) = √1 - 4/9 ≅ 0.745

(42º + 180º = 222º ← angle is located in Quadrant III).