I attached a photo where I graphed these vertices in order to count the length and width. After counting the number of units between R & U I got a width of 4. And then I counted the units between S & T to get a width of 6. Using the formula to calculate the perimeter of a rectangle, P = 2(l+w). The perimeter is 20.
First I added the length plus the width, 4 + 6 and got 10. Then I did 10 x 2 which is how I got a perimeter of 20.
