Question 499471
There are different methods of solving this, but the first step is to plot all the points on a graph.  Next, you can either use the distance formula, simply count the squares, or use the pythagorean theorem.  You can count squares for all but 1 side and I would recommend using the pythagorean theorem to find that side.

The side lengths are 5,4,2,5
therefore, the perimeter is the distance around the quadrilateral, which is 
5+4+2+5=16.  There may be units for this as well, so make sure you include units.