The percentage of ( a% ) is to be applied on the principal amount of ( P ):
We need to determine what percentage proportion rate ( a% ) will left us with a disposable amount of ( D ):
The percentage formula applied at principal amount is:
We will plug in the values the respective values as follows:
The amount of percentage reduction applied to the principal amount is ( 2% ) and $645.07 is 98% of principal $658.23.
Hence,