A deposit of $300 is made into an account that earns 2.5% annual interest, compounded continuously. No other deposits or withdrawals are made. To the nearest penny, how much money will be in the account after exactly 20 years?

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?