$920 would be the amount of interest in the first payment.
We convert the decimal to a monthly amount first. (5.5/100)/12 = 0.0046. We then multiply this by the amount of the loan, 200,000:
200000*0.0046 = 920.
$920 of the first month's payment would go towards interest.
To find the percentage of the payment, you would divide this amount by the amount of the first month's payment.
