1 year = 12 months.
30 years x 12 months per year = 360 total months
Multiply total months by monthly payment:
360 months x 1,073.21 per month = $386,355.60 total monthly payments for 30 years.
Now add the down payment to the total monthly amount:
$386,355.60 + $45,000 = $431,355.60
Total amount paid: $431,355.60