Textbook Page 62 #26

Four points, A, B, C and D, have the following coordinates:
A) 0.75, 0.81
B) 0.75, -0.65
C) -1.22, -0.65
D) -1.22, 0.81
What is the area of quadrilateral ABCD, to the nearest hundredth of a square unit?

This is how I solved this question:

The area of quadrilateral ABCD to the nearest hundredth of a square unit is -2.33 sq.unit.