Final answer:
The correct answer is option B. In triangle ABC with given side lengths and angle, we can find the length of side AC and measure of angle A using the Law of Cosines.
Step-by-step explanation:
In triangle ABC, we are given that AB = 12, BC = 18, and ∠B = 75°.
To find the length of side AC, we can use the Law of Cosines, which states that c² = a² + b² - 2ab cos C.
Using the given information, we can substitute the values into the equation: AC² = 12² + 18² - 2(12)(18)cos(75°).
By solving this equation using a calculator, we find that AC ≈ 18.9 units and the measure of angle A ≈ 39.1°.
Therefore, the approximate length of side AC is 18.9 units and the measure of angle A is 39.1°.