$3.$ You are buying a new house, and you have negotiated a $15-$year mortgage loan with a local bank for an amount $$361,000$ at $4\mathrm{.}52$ percent APR with monthly compounding. What would your monthly payment be$?$ Round it to two decimal place $($cents$),$ e$.$g$.,234\mathrm{.}56.$

$4.$ Suppose you plan to retire in $40$ years. If you make $10$ annual investments of $$4,000$ into your retirement account for the first $10$ years, and then no more contributions to the account for the remaining $30$ years. If the retirement account earns a fixed $5\%$ annual interest, how much will you have at your retirement? Round it to two decimal places without the $ sign, e$.$g$.,1234567\mathrm{.}89.$