Abe starts working out at a gym and begins to lose weight. His weight can be calculated using the equation y = 250 − 3x where y is his current weight and x is the number of weeks he has been working out. Which statement best describes Abe’s weight loss? help me pls

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?