If sin(θ) = 8/17 and θ terminates in QI, find cos(θ)

Answer 1

sinØ = 8/17
y = 8, r = 17
x^2 + 8^2 = 17^2
x^2 = 225
x = ± 15 , but we are told Ø is in quad I
so x = 15
cosØ = x/r = 15/17