1. An equilateral triangle

2. There are 6 corners. Slicing off a corner results in a new face that is square.

3. A truncated octahedron has 6 square faces and 8 hexagonal faces.
   

Solution

Student answers may vary. Two copies of the pattern below can be used to make the model. Surround a regular hexagon with squares and other hexagons as shown. Glue or tape faces together using the tabs. This will make a cup-shaped figure that is half of the completed solid. Repeat the process for the other half of the solid.