Here’s a simple-sounding problem: Imagine a circular fence that encloses one acre of grass. If you tie a goat to the inside of the fence, how long a rope do you need to allow the animal access to ...

She’s right—using simultaneous equations does get really complicated, and if you’d like to send me your work for the solution, I’d love to see it. But the system is also kind of a trick. Like a sudoku ...