解：?$(1) $?由于?$M$?和?$N$?分別是點(diǎn)?$O$?關(guān)于?$P A$?和?$P B$?的對稱點(diǎn)
∴?$OE=ME，$??$OF=FN$?
∴?$C_{?OEF}=OE+EF+OF$?
?$=ME+EF+FN=MN=6$?
?$ (2) $?由于?$M$?和?$N$?是?$O$?關(guān)于?$P A$?和?$P B$?的對稱點(diǎn)
∴?$∠MP A=∠OP A，$??$∠NP B=∠OP B$?
∴?$∠MPN=2∠AP B$?
∵?$∠AP B=α$?
∴?$∠MPN=2α$?
