Graph by plotting points f(x)=3x+1; (-2,2)

Find the value of the variable and the length of each secant segment.

Pls brainliest will be awarded if answer is correct

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?