To find the height of a parallelogram, you can use the formula for the area of a parallelogram:

$\text{Area} = \text{Base} \times \text{Height}$

Given that the area is 12 square units and the base is 9 units, you can substitute these values into the formula:

$12 = 9 \times \text{Height}$

To solve for the height, divide both sides by 9:

$\text{Height} = \frac{12}{9} = \frac{4}{3} \text{ units}$

So, the height is $\frac{4}{3}$ units.

Would you like further details or have any questions?

Here are some related questions you might find interesting:

1. What is the formula for the area of a parallelogram when given two sides and an angle?
2. How would the height change if the area were doubled but the base remained the same?
3. Can the height of a parallelogram be longer than its base?
4. What happens to the area if both the base and height are tripled?
5. How do you find the height of a parallelogram if only the diagonals are known?

Tip: Always remember that the height in a parallelogram is the perpendicular distance from the base to the opposite side, not necessarily the side length.