Solution:
Given:
4θ is an acute angle,
And cot 4θ = tan (θ - 5°).
Formula used:
tan (90° - θ) = cot θ
Calculation:
cot 4θ = tan (θ -5°)
⇒ tan (90° - 4θ) = tan (θ -5°)
⇒ 90° - 4θ = θ -5°
⇒ 90° + 5° = θ + 4θ
⇒ 95° = 5θ
⇒ θ = 19°
∴ the value of θ is 19°.