The angle θ lies in Quadrant I. sinθ=2/5 What is cosθ?

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