The MP3 player Sean wants to buy costs $124. He has saved up one-third of the price. About how much money has Sean saved? a. $45
b. $30
c. $35
d. $40

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?