Stephen purchases a square-shaped canvas to use for a painting. the diagonal of the square is 10 inches longer than the length of its sides. stephen uses the pythagorean theorem to create the equation x2 + x2 = (x + 10)2 to determine the side length, x, of the canvas. the side length of the canvas is best found by because the equation is . solving the equation produces two measurements, and must be discarded for being unreasonable.