You are standing 10 feet away from the tree. You are looking at the very top of the tree. You see a huge, delicious plum hanging from one of the branches. This plum happens to be hanging 30 feet in the air. Thirty feet is a bit too high for you to simply reach up and grab the plum. What will help you to get to this delectable piece of fruit? You need a ladder. But what size ladder do you need?