You went out to eat with 3 friends and your meal cost $82.50. How much was the bill if 6.75% sales tax was included?
How much would you tip the waiter, if you wanted to leave a 20% tip?

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?