What would 672,831 be rounded to the nearest hundred

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?

What is the slope of the line passing through the points (-5, 7) and (-3,5)?

If wxyz is a square, which statements must be true?