Keep in mind its been a while since i did this type of work lol.....
did you try to draw it out on a grid paper....what will be helpful is if you got the coordinates and put the points down and then if you connect the dots you get your shape now you will count the unis in which the width and length is timed. so like if you had grid and it gave you coordinates and you did all that now you will count how many units is in the width and how many in the length. but your best answer might be 14 units x 4 units