Answer:
B. -0.07
Explanation:
Apply the Law of signs find θ.
Cos θ = (a² + b² - c²)/2ab
Where,
a = 7
b = 8
c = 11
Plug in the values
Cos θ = (7² + 8² - 11²)/2*7*8
Cos θ = (49 + 64 - 121)/112
Cos θ = -8/112
Cos θ = -0.0714285714
Cos θ = -0.07 (to 2 decimal places)