How do you use coordinates to find the perimeter and area of polygons?

Question

anonymous · Answer

look up that same thing on google u will find A  good answer

jdoe0001 · Answer

well, once you have the coordinates for the points for the polygon, namely the vertices, then you get their distances,                  $\bf \textit{distance between 2 points}\ \quad \
\qquad 
d = \sqrt{(x_2-x_1)^2 + (y_2-y_1)^2}$

anonymous · Answer

I tried but I need an answer that is easy to understand

tkhunny · Answer

Find the distance between each external vertex.

anonymous · Answer

I have this much so far...how do I finish? 
to divide a segment you first have to find the distance between the X and Y coordinate. then you multiply each distance by the particular ratio given. lastly you connect

tkhunny · Answer

"I tried but I need an answer that is easy to understand "

This makes little sense.  Who ever said the concept was easy to understand?  You need the ability to perform whatever process is required and the understanding of why you are doing it.  It has nothing to do with easy or hard.  It is what it is.