We are given vertices of a rectangle (0, −4) ,  (−1, −3)  , (2, 0) , and (3, −1).
Length is the distance between (0, −4) and  (−1, −3) points.
Width is distance between (−1, −3)  and (2, 0) points.
Computing length:



Computing Width : 



Area of the rectangle = Length × Width 
= 
 .
.