\[\boxed{\mathbf{344\ (344)}.\ Еуроки\ - \ ДЗ\ без\ мороки}\]
\[a = 24\ см.\]
\[b = a + 18\ см = 24 + 18 =\]
\[= 42\ см.\]
\[c = b\ :2 = 42\ :2 = 21\ см.\]
\[P_{\mathrm{\Delta}} = a + b + c =\]
\[= 24 + 42 + 21 = 87\ см.\]
\[Ответ:87\ см.\]
\[\boxed{\mathbf{344}\mathbf{\ (307)}.\ Еуроки\ - \ ДЗ\ без\ мороки}\]
\[\angle ABC = 106{^\circ};\ \ \ \angle ABD = 34{^\circ}.\]
\[\angle DBC = \angle ABC - \angle ABD =\]
\[= 106{^\circ} - 34{^\circ} = 72{^\circ}.\]
\[Ответ:\ \ 72{^\circ}.\]