1. **Problem statement:** We have a 30-60-90 right triangle with the side opposite the 30° angle equal to 12, and we need to find the length of side $b$, which is adjacent to the 30° angle. 2. **Recall the properties of a 30-60-90 triangle:** The sides are in the ratio $1 : \sqrt{3} : 2$, where: - The side opposite 30° is the shortest side (length $x$), - The side opposite 60° is $x\sqrt{3}$, - The hypotenuse is $2x$. 3. **Identify the given side:** The side opposite 30° is given as 12, so $x = 12$. 4. **Find side $b$:** Side $b$ is adjacent to the 30° angle, which means it is opposite the 60° angle. Therefore, $b = x\sqrt{3} = 12\sqrt{3}$. 5. **Final answer:** $$b = 12\sqrt{3}$$