Arnold has been given a 6 foot by 6 foot sheet of cardboard to make an open box by cutting an equal size square from each corner, folding up the resulting flaps, and taping at the corners. your task is to label dimensions on a sketch with same size variable cut from each corner.

Fists we are going to sketch our cardboard sheet; since the length and the width are equal, we know that our figure will be a square in which each side will be 6 foot long. Now, we need to cut an equal size square form each corner, but we don't now how long the lengths of the square will be, so we are going to assign the variable  to each sides of our square as you can see in the picture.