Step 1: Note adjacency in the net.
In the given cross-shaped net, the $\triangle$ face shares edges with three faces (those directly touching it in the flat layout). The face that will be opposite the $\triangle$ in the folded cube is the unique face that does not share an edge with $\triangle$ and is not co-linear with it in the final wrap.
Step 2: Simulate the fold mentally.
Fold the horizontal strip inward to form the lateral surface, then fold the remaining flap to close the cube. Under this folding, the $\bullet$ face comes to the position directly opposite $\triangle$ (while the other three adjacent faces wrap around it as neighbors).
Step 3: Conclusion.
\[
\boxed{\text{Opposite to }\triangle\text{ is }\bullet}
\]