Bake a single cube from three wax cubes with edges of [[$ 3 $]] cm, [[$ 4 $]] cm and [[$ 5 $]] cm. Calculate the length of this edge. By what percentage of does the total area of the cubes change? (Finnish matriculation exam, spring 1994)

Take a picture of your solution and return it to the submission folder.

Answer: The area decreases by [[$ \% $]].