What equal series of payments must be paid into a sinking fund in order to accumulate each given amount? (a) $9,000 in 12 years at 9% compounded semiannually when payments are semiannual. (b) $2,000 in 14 years at 8% compounded quarterly when payments are quarterly. (c) $31,000 in four years at 8.65% compounded monthly when payments are monthly. (a) The required semiannual payment should be \$ (Round to the nearest cent.)