Answer:
5 units
Explanation:
Next time please supply the formula, which was apparently given in this question:
A = (1/2)(base)(height)
Here, A = 30 units^2 = (1/2)(12 units)(height), or
30 units^2 = (6 units)(height)
Solving for (height), we get
30 units^2
(height) = ------------------ = 5 units
6 units
The height is 5 units