It's a geometry question. You have to measure the length from one corner to the peak of the tent. That will give you 7.5 feet on one side, and your measure length for the other side. Now, all you need to do it measure the angle of the two. Using the proper calculations, you can find the height of the center pole, it was sitting on the ground. Just add the height of one corner pole, and boom, you've got the height of the center pole. Have fun with that.