Chris has $1,500 in the bank and takes out of the money. He decides to use e of the money he took from
his account to pay part of a $700 debt. After he makes this payment, how much will he still owe?

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?