check the picture below.
now, you can pretty much count the units off the grid for the segments ST and RU, so each is 7 units long, and are parallel, meaning that the other two segments are also parallel, and therefore the same length each.
so we can just find the length for hmmmm say SR, since SR = TU, TU is the same length,
[tex]\bf ~~~~~~~~~~~~\textit{distance between 2 points}
\\\\
S(\stackrel{x_1}{-2}~,~\stackrel{y_1}{1})\qquad
R(\stackrel{x_2}{-5}~,~\stackrel{y_2}{5})\qquad \qquad
% distance value
d = \sqrt{( x_2- x_1)^2 + ( y_2- y_1)^2}
\\\\\\
SR=\sqrt{[-5-(-2)]^2+[5-1]^2}\implies SR=\sqrt{(-5+2)^2+(5-1)^2}
\\\\\\
SR=\sqrt{(-3)^2+4^2}\implies SR=\sqrt{25}\implies SR=5[/tex]
sum all segments up, and that's perimeter.
