Step 1: Recall the property of similar triangles.
In two similar triangles, the ratio of any corresponding linear dimensions (such as sides, altitudes, medians, or angle bisectors) is the same as the ratio of their corresponding sides.
Step 2: Apply the property to the altitudes.
Since the ratio of the corresponding sides of the two triangles is \( 2 : 3 \), the ratio of their corresponding altitudes will also be \( 2 : 3 \).
Final Answer: The ratio of the corresponding altitudes is \( \mathbf{2 : 3} \), which corresponds to option \( \mathbf{(3)} \).