I need to know how to work out the area of a quadrilateral with to coordinates of A(-7,0) B(2,3) C(5,0) D(-1,-6).
Would I be right in thinking I would do this:
A and C lies on the x-axis.
B and D are heights
Split as two triangles and sum (ABC +ADC)
Would this be correct if not where am I going wrong?