Given that,
The area parameters are
A = 2.7 cm, B = 4.1 cm C = 4.5 cm
We want to find the angle extended by B.
Using cosine Rule
b² = a² + c² - 2ac•Cosθ
4.1² = 2.7² + 4.5² - 2 × 2.7 × 4.5• Cosθ
16.81 = 7.29 + 20.25 - 24.3•Cosθ
16.81 - 7.29 - 20.25 = -24.3•Cosθ
-10.73 = -24.3•Cosθ
Cosθ = -10.73 / -24.3
Cosθ = 0.4416
θ = Cos~1 (0.4416)
θ = 63.8°
The angle B is 63.8°
