What is the area of the polygon shown below? (in the image). A. 322 mm^2 B. 364 mm^2 C. 520 mm^2 D. 584 mm^2 Show all work please!

Answer:
A. 322 mm^2
Step-by-step explanation:
First split the shape into two (a rectangle and a triangle).
Then calculate the area of those shapes.
Rectangle: 20 x 14 = 280 mm^2
Triangle: 6 x 14 / 2 = 42 mm^2
Add them together.
280 + 42 = 322 mm^2