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
�
m
400π m400, pi, start text, space, m, end text.
What is the diameter
�
dd of the lake?
�
=