To find the area of the rectangle, you have to multiply the length by the width.
The first pairs of coordinates are (11, 1) and (-5, 1). You can see that the change in x is 16. This means that the length is 16.
The next pairs of coordinates are (-5, 4) and (-5, 1). Here you can see the change in y is 3, so the height is 3.
16 x 3 = 48, the area is 48 units squared.
