Which of the following ordered pairs are y-intercepts? Check all that apply. (4.0)
0 (-1, 1)
(0.0)
(0.-7)
0 (-2,-2)
(0, -0.25)

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?