We can use the pythagorean theorem to find this answer. [tex]a^2 + b^2 = c^2[/tex] where a and b are the triangle legs and c is the hypotenuse. In this case, we're missing one of the legs. [tex]7^2 + b^2 = 8^2[/tex] [tex]49 + b^2 = 64[/tex] [tex]b^2 = 15[/tex] [tex] b = \sqrt{15}[/tex] Therefore, the missing side is approximately is 3.88.