What is the area of quadrilateral WXYZ?

Answer:
[tex]Area = 105[/tex]
Step-by-step explanation:
Given
[tex]W = (-5,4)[/tex] ---- [tex](x_1,y_1)[/tex]
[tex]X = (3,4)[/tex] ------ [tex](x_2,y_2)[/tex]
[tex]Y = (6,-6)[/tex] ----- [tex](x_3,y_3)[/tex]
[tex]Z = (-7,-6)[/tex] ---- [tex](x_4,y_4)[/tex]
Required
Determine the area;
Area is calculated as thus:
[tex]Area = \frac{1}{2}[(x_1.y_2 +x_2.y_3 + x_3.y_4 + x_4.y_1)-(x_2.y_1 +x_3.y_2 + x_4.y_3 + x_1.y_4)][/tex]
Substitute values
[tex]Area = \frac{1}{2}[(-5*4 +3*-6 + 6*-6 + -7*4)-(3*4 +6*4 + -7*-6 + -5*-6)][/tex]
[tex]Area = \frac{1}{2}[(-102)-(108)][/tex]
[tex]Area = \frac{1}{2}[-102-108][/tex]
[tex]Area = \frac{1}{2}[-210][/tex]
[tex]Area = -105[/tex]
[tex]Area = 105[/tex]
None of the options answer the question: