Can you answer the question and write how.

Here is the are of the shaded region

shaded = rectangle      - parallelogram
245       = 20(3a-10)     - 5(2a-9)

Keep in mind that:
- area of a rectangle = length * width
- area of a parallelogram = one side length * consecutive side's length

So, we have:
245 = 60a - 200 - 10a + 45

solve for a now:::
245 = 50a - 155

50a = 245+155 = 400

a=400/50 = 8

a=8

I hope you got the idea

The american colonies would have been ruled by a king.