12.
Area of a triangle = (bh)/2
Counting the squares in the figure, the base (bottom) of the triangle looks to be about 8. The height looks like 5.
b = 8
h = 5
A = (8*5)/2
A = (40)/2
A = 20
So the closest answer would be
A. 21.5 square units
13.
Area of a trapezoid = [(b₁ + b₂)/2]h
b₁ = 3
b₂ = 9
h = 6
A = [(3 + 9)/2]6
A = [12/2]6
A = (6)6
A = 36
Since I can't see the answer choices, it would be the closest number to 36.