Answer:
sqrt21/5
Step-by-step explanation:
You can solve this by taking advantage of the trigonometric identity of sin^2(x) + cos^2(x) = 1
So square sinθ to get, 4/25
Subtract that from one to get:
cos^2(θ) = 21/25
Take the square root to get:
cosθ = sqrt21/5
