Answer
A=16
Work Step by Step
To form a rectangle the fourth point must have the same x coordinate as the point below it (point A) and the same y coordinate as the point to the right of it (point C).
Therefore point D is located at (2,3).
h=|y$_b$-y$_c$|
h=|-1-3|
h=4
b=|x$_a$-y$_b$|
b=|2-6|
b=4
A=bh
A=4(4)
A=16