The sum of x and 3/5 is 5/7 .
what is the value of x?
enter your answer in the box as a fraction in simplest form.
x =

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?