1985 AJHSME Problems/Problem 11
Problem
A piece of paper containing six joined squares labeled as shown in the diagram is folded along the edges of the squares to form a cube. The label of the face opposite the face labeled is
Solution
To find the face opposite , we can find the faces sharing an edge with , so the only face remaining will be the opposite face.
Clearly, and share an edge with . Also, the faces , , and share a common vertex, therefore shares an edge with . Similarly, the faces , , and share a common vertex, so shares an edge with .
The only face doesn't share an edge with is , which is choice