Find out the length of each side. For the slanty sides, you can do this by using the formula
[tex]d = \sqrt{(y2-y1)^{2} +(x2-x1)^{2} }[/tex]
For the straight sides (like the one on the bottom and the one on the left), just use simple subtraction.
Add up all 4 sides and you get the perimeter. You should get 20, 15, [tex]5\sqrt{5}[/tex] and [tex]5\sqrt{26}[/tex]. The total is 35 + [tex]5(\sqrt{26} +\sqrt{5} )[/tex].
