$\frac{\left|CE\right|}{6}=\frac{12}{5}$

$\left|CE\right|\cdot 5=6\cdot 12$

$\left|CE\right|\cdot 5=72$         $/:5$

$\left|CE\right|=14,4$

 

$\frac{6}{\left|ED\right|}=\frac{6+14,4}{\left|CF\right|+8}$

$\left|CF\right|=\left|ED\right|$

$\frac{6}{\left|ED\right|}=\frac{20,4}{\left|ED\right|+8}$

$6\left(\left|ED\right|+8\right)=\left|ED\right|20,4$

$6\left|ED\right|+48=20,4\left|ED\right|$

$48=20,4\left|ED\right|-6\left|ED\right|$

$48=14,4\left|ED\right|$

$\left|ED\right|=3\frac{1}{3}$

$O=2\cdot 3\frac{1}{3}+2\cdot 14,4=2\frac{2}{3}+28,8=6\frac{2}{3}+28\frac{4}{5}=6\frac{10}{15}+28\frac{12}{15}=34\frac{22}{15}=\underline{\underline{35\frac{7}{15}}}$