Answer:
Option (3)
Step-by-step explanation:
By applying cosine rule in the triangle ABC,
BC² = AC² + AB² - 2(AC)(AB)cosA
5² = 3² + 7²- 2(3)(7)cosA
25 = 9 + 49 - 42cos(A)
25 = 58 - 42cos(A)
cos(A) = [tex]\frac{33}{42}[/tex]
A = [tex]\text{cos}^{-1}\frac{11}{14}[/tex]
A = 38.21°
A ≈ 38°
Option (3) will be the correct option.
