I have a few worded problems i have no clue how to go about solving... there are diagrams, but i don't think i can draw it online, but i think the question is a bit explanitory, so lets see how it goes.

A private company will accept a box for domestic shipment only if the sum of its length and girth (distance around) does not exceed 102 in. What dimensions will give a box with a square end the largest possible volume?