What is the area in square units of the convex quadrilateral with vertices (-1, 0), (0, 1), (-2, 0) and (0, -3)?
+1223 You can use the shoelace theorem.
-1 0
0 1
-2 0
0 -3
-1 0
-----------------
left side sum: 0 * 0 + 1 * (-2) + 0 * 0 + (-3)(-1) = 1
right side sum: -1 * 1 + 0 * 0 + (-2)(-3) + 0 * 0 = 5
area: (1/2) * |1 - 5| = 2
