Need help with this thing

Which formula gives the area of a triangle? a=1/2(b+h)

For the following sequence determine the common difference (if it is an arithmetic sequence) or the common ratio (if it is a geometric sequence).

You have just applied, and have been approved for a $58,000 mortgage. the rate quoted to you by the lender is 6.1% for a 30 year fixed mortgage. determine how much of your third month’s payment goes towards the principal. $56.65 $56.93 $57.22 $57.51