M5L1 Please help

Kenton decides to go visit his brother, Darius, and roommate, Troy, for the weekend. To pay them back for letting him stay at their place, Kenton agrees to wait for their new wall unit to be delivered for their living room and let the delivery people know where it needs to be set up. Troy is in college and not only does he love math but he enjoys playing practical jokes on people. The directions Troy leaves state that the wall unit is ft long and the dimensions of the living room are 9 ft wide by 11 ft long. Kenton needs to figure out which wall to get the wall unit set up on, but he does not have a calculator.

Given the shape of the room and hallways, the delivery workers will have to use the front door if
the wall unit will be on an 11-ft wall or the back door if the wall unit will be on a 9-ft wall. Which
door should Kenton tell the delivery workers to enter to be sure that the wall unit fits? (Remember that you can’t use a calculator to answer this question.)