What is the area in square units of the convex quadrilateral with vertices $(-1, 0)$, $(0, 1)$, $(2, 0)$ and $(0, -3)$?
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
What is the area in square units of the convex quadrilateral with vertices $(-1, 0)$, $(0, 1)$, $(2, 0)$ and $(0, -3)$?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
6
What is the area in square units of the convex quadrilateral with vertices $(-1, 0)$, $(0, 1)$, $(2, 0)$ and $(0, -3)$?
train