Collin was helping his uncle clean up a construction site. Collin’s job was to make a neat stack of scrap wood. Each piece of wood was 1 3/8 inches thick. At the end of the day, Collin’s stack was 57 3/4 inches tall. How many pieces of wood were in collin’s stack

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?