A factory that makes granola bars uses 1⁄6 of a barrel of raisins in each batch. Yesterday, the factory used 5⁄6 of a barrel of raisins. How many batches did the factory make yesterday?

You are standing next to a really big circular lake. you want to measure the diameter of the lake, but you don't want to have to swim across with a measuring tape! you decide to walk around the perimeter of the lake and measure its circumference, and find that it's 400\pi\text{ m}400? m. what is the diameter dd of the lake?