To determine the length of side \( a \) given that side \( b \) is 12 meters, we first need to understand the equation relating sides \( a \) and \( b \). Since the information doesn’t specify an equation directly, it seems we might be looking at a geometric figure and possibly a relationship often seen in rectangles or right triangles.
Since it's stated that \( a = (12) \) in the first part (presumably suggesting both sides may be equal), we might assume that if side \( b \) is 12 meters, and \( a \) should also be the same for some simple geometric figure like a rectangle.
Given that:
- If \( a = 12 \), the possible choice based on similar assessment would lead us to conclude that side \( a \) should also be 12 meters if we are maintaining equality.
So, if side \( b \) is 12 meters, the most logical conclusion for side \( a \) in the context of equality would be:
12 meters