To calculate the monthly interest rate \( r \) for the 30-year loan with an interest rate of 4.5%, you can follow these steps:
-
Convert the annual interest rate to a decimal:
\[ \text{Annual Interest Rate} = 4.5% = \frac{4.5}{100} = 0.045 \] -
Calculate the monthly interest rate:
To find \( r \), divide the annual interest rate by 12 (the number of months in a year):
\[ r = \frac{0.045}{12} \] -
Perform the division:
\[ r = 0.00375 \]
So, the monthly interest rate \( r \) for the 30-year loan is \( 0.00375 \), or 0.375%.