Given,

5 tan θ – 4 = 0

So,

5 tan θ = 4

tan θ = 4/5

In ∆ ABC,

AC² = AB² + BC²

AC² = (4)² + (5)²

AC² = 16 + 25

AC² = 41

AC = √41

Therefore,

sin θ = AB/AC = 4/√41

cos θ = BC/AC = 5/√41

Now,