Hello. Pre-cal practice work for test tomorrow.

Problem gives us these coordinates: A(1,2), B(5,2), C(3,6), D(5, -3)

I graphed it. How are we supposed to find the area with these coordinates?

I know the answer is 16, because I checked the back of the book. I would like to know how to get that answer.

Thank you

Oh yes, I apologize for the misconveniance.. I will correct this when I get back to my room to access my pre-cal book.