It is given that the triangles ITH and APG are congruent.
When the two triangles are congruent, then the corresponding angles and sides are congruent to each other.
By being congruent, the corresponding angles which are congruent are:

Therefore, 
SO, Option 2 is the correct answer.
Let's call trade balance b, exports e and imports i.
We now construct formula.

Put in the data from last year.

U.S trade balance for that year is -690 billion dollars.