I graphed these vertices myself in the attached photo, and it turned out to be a rectangle; With the thought that you perhaps made a typo and meant rectangle instead of polygon I continued on and found the perimeter of the rectangle.
The formula for finding the perimeter of a rectangle is P = 2(l+w).
I counted the units of the long side (K & J) to get the length, which is 7.
Next, I counted the units between J & H to find the width which is 4. Now we're ready to use the formula.
First I will add the length plus the width, 7 + 4 = 11.
Then I will multiply 2 x 11 to get a product of 22.