\[\boxed{\mathbf{2}\mathbf{.}\mathbf{82}}\]
\[MN = 47\ см.\]
\[\textbf{а)}\ MK = 13\ см;\ \ PN = 18\ см:\]
\[KP = MN - (KN + MK) =\]
\[= 47 - (13 + 18) = 47 - 31 =\]
\[= 16\ см.\]
\[\textbf{б)}\ MP = 34\ см;KN = 18\ см:\]
\[PN = MN - MP = 47 - 34 =\]
\[= 13\ см.\]
\[MK = MN - KN = 47 - 18 =\]
\[= 29\ см.\]
\[KP = MN - (MK + PN) =\]
\[= 47 - (13 + 29) = 47 - 42 =\]
\[= 5\ см.\]
\[Ответ:а)\ 16\ см;б)\ 5\ см.\]