To prove that the triangle is scalene, calculate all the lengths of the sides.
The formula for a line like this is basically pythagorean theorem, which is
[tex]p = \sqrt{ {(y2 - y1)}^{2} + {( x2 - x1})^{2} } [/tex]
(x1, y1) and (x2, y2) are the respective vertexes.
