Given:
The unpaid balance on her credit card is $57200.
The interest rate per month is 1.30%.
To find:
The interest amount.
Step-by-step explanation:
The interest amount is calculated as follows,

Therefore, the interest amount that needs to be charged for 1 month is $743.6.
Final answer:
The interest amount that needs to be charged for 1 month is $743.6.