\[\boxed{\mathbf{260\ (260)}\mathbf{.}\mathbf{\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[\frac{171 \cdot 1001}{181 \cdot 1001} = \frac{171171}{181181}\]
\[\frac{171}{181} = \frac{171171}{181181}\]
\[\boxed{\mathbf{260}\mathbf{.}}\]
\[P = 15 \cdot 2 + 6 \cdot 2 = 30 + 12 =\]
\[= 42\ см.\]
\[Ответ:42\ см.\]