Question 419624
I would do the same as the other tutor did. However, there is no need to memorize the "formula"; it is based directly off of the Pythagorean theorem. You are in essence trying to find the hypotenuse of a triangle with base {{{x[2] - x[1]}}} and height {{{y[2] - y[1]}}} (also note that the order of the {{{x[i]}}}, {{{y[i]}}} doesn't matter because it is being squared).