our-step to the base. LESSON 1: Solving Problems involving the Missing Base, Percentage, and Rate In solving problems involving base, percentage, or rate, you must understand the relationships among them. At a constant rate, the percentage is directly proportional The unknown quantity can be identified from the given two values. For example, if the percentage is missing in the word problem, the base and the rate must be given Some words can give hints as to what is given or missing in a word problem. As an example, the quantity with the percent (%) symbol is the rate. The base refers to the total quantity or the whole and is usually preceded by the word of in a sentence. On the other hand, the percentage is a part of the base. Teehan's triangle is one of the tools that you can use to help you solve problems with unknown base, percentage, or rate.​