National Bank issued a loan of $$59,000$ at $6\mathrm{.}43\%$ compounded semi$-$annually. The loan was repaid by payments of $$990$ at the end of every month.

a$.$ How many payments were required to pay off the loan?

$($Enter a whole number$)$

b$.$ What was the total principal fepaid in the $4$ th year?

$($Enter starting and ending periods as P$1$ and P$2$ and the total principal repaid as a positive value to the nearest cent.$)$

$P1=,P2=$

Total principal repaid in the $4$ th year $=$$

c$.$ What was the size of the final payment?

$($Enter a positive value to the nearest cent$)$

$