Tina bought these supplies to finish her project: two art brushes, one jar of paste, four dowel rods (each are 1/2 in. long), and three jars of paint. how much change will she get from $20?

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?