We we go through the chart provided here , the tax applied on your income is based on Income group and your status. Here Raoul is head of the household and his income falls in group $38400 to $38450. In this category the tax applied it $5144. He has already paid $4428. Hence remaining amount to be paid is their difference that it $716.
Hence he is supposed to make additional payment of $716 as tax towards his income earned
Step-by-step explanatii just took the test and it was right. the base would be 20 and the height would be 10. from there you just you the formula for area of a right triangle.