Solution :
Given that in the right triangle , ∠A=30° and AB = 12√3 .
As the figure is missing and its not clearly mentioned that AB is the base or hypotenuse of the right triangle. So two cases arises-
Case 1: AB is the base for ∠A of the right triangle (as shown in figure 1).
As we know from the trigonometric ratio that,

Here , AB is the base and AC is the hypotenuse , and ∠A=30°

The value of


Hence, AC is 24 unit long.
Case 2: AB is the hypotenuse for ∠A of the right triangle (as shown in figure 2).
As we know from the trigonometric ratio that,

Here , AB is the hypotenuse and AC is the base, and ∠A=30°

The value of


Hence, AC is 18 unit long.