What is the area of the trapezoid? 30 square units
60 square units
90 square units
120 square units

  60 square units

Step-by-step explanation:

We can bound the trapezoid with a rectangle having opposite corners at (4, 6) and (16, 16). This rectangle will have an area of (16 -4)(16 -6) = 120 square units.

From this bounding rectangle we can subtract the areas of the corner triangles. Their x-y extents (CW from upper left) are ...

  (10×6), (2×6), (6×4), (6×4)

Their areas are half the product of these base×height dimensions, so the triangles have a total area of ...

  (1/2)(60 +12 +24 +24) = 60

Then the area of the trapezoid is the difference of the area of the bounding rectangle and the area of the corner triangles:

  trapezoid area = 120 -60 = 60 . . . . square units