What is the area of the trapezoid?
A 112.5 mm^2
B 72 mm^2
C 40.5 mm^2
D 56.25 mm^2

the answer is B. 72 mm^2 because
9x4.5=40.5
then
7x4.5=31.5
then
40.5+31.5=72.0 mm^2