What do you have when you snap your fingers two times every second

The chart below shows the distribution of weeds in yard

Which of the choices shown could be used to prove that aacp=abcp ?

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?