Answer:
A rectangle with a base of 4 units and height of 2 units.
Explanation:
Draw a parallelogram with the parallel 6-inch sides on top and bottom.
Then draw vertical altitudes inside the parallelogram, from a vertex to the opposite side, one on each side.
There is one triangle on each side. Move one triangle from one side to the other.
Now you have a rectangle that may have a bottom and top sides of 4 inches, and vertical sides of 2 inches.
Answer: A rectangle with a base of 4 units and height of 2 units.