Can y’all please solve

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?

Graph the line with the given slope m and y-intercept b. m=-3,b=1

Sawsan recorded the favorite sport of students at her school. she surveyed 200 students. how many students chose tennis?