Answer :
The cosine rule is used to determine the values of unknown aides and angles in a triangle
The measure of θ is approximately 117.2°
Reason:
Given parameters are;
The distance between the two windmills, a = 456 feet
The distance between the cow and one of the windmills, b = 320 feet
Distance between the cow and the other windmills, c = 210 feet
Required, the angle θ between b, and c direction
Solution;
By cosine rule, we have;
a² = b² + c² - 2·b·c·cos(θ)
- [tex]cos (\theta) = \dfrac{b^2 + c^2 - a^2}{2 \cdot b \cdot c }[/tex]
Which gives;
[tex]cos (\theta) = \dfrac{320^2 + 210^2 - 456^2}{2 \times 320 \times 210 }[/tex]
- [tex]\theta = arcos \left(\dfrac{320^2 + 210^2 - 456^2}{2 \times 320 \times 210 }\right) \approx 117.2 ^{\circ}[/tex]
The measure of θ ≈ 117.2°
Learn more about the cosine rule here: