Answer:
Step-by-step explanation:
hello :
cos²θ +sin²θ = 1 and cosθ =4/5
(4/5)² + sin²θ = 1 so : sin²θ = 1 - 16/25
sin²θ = 9/25 = (3/5)²
sinθ = 3/5 or sinθ = - 3/5 because : (3/5)²= (- 3/5)²= 9/25
