8. (10 points) As shown in the figure, the area of trapezoid $ABCD$ is 320, the area of parallelogram $CDEF$ is 240, and the area of triangle $OCD$ is $\qquad$

保留源文本的换行和格式，直接输出翻译结果。
【Solution】Solution: According to the analysis, $\frac{\text { trapezoid } \mathrm{ABCD} \text { 's area }}{\text { parallelogram } \mathrm{CDEF} \text { 's area }}=\frac{\frac{1}{2}(\mathrm{CD}+\mathrm{AB})}{\mathrm{CD}}$
$$
\begin{array}{l}
\Rightarrow \frac{320}{240}=\frac{C D+A B}{2 C D} \Rightarrow \frac{C D}{A B}=\frac{3}{5} \Rightarrow \frac{C O}{O A}=\frac{3}{5}, \\
\Rightarrow \frac{S_{\triangle D O C}}{S_{\triangle C O B}}=\frac{D O}{B O}=\frac{C 0}{O A}=\frac{S_{\triangle A O D}}{S_{\triangle A O B}}=\frac{3}{5}, \\
\Rightarrow \frac{S_{\triangle C O D}+S_{\triangle A O D}}{S_{\triangle C O B}+S_{\triangle A O B}}=\frac{3}{5}, \\
\Rightarrow \frac{S_{\triangle A C D}}{S_{\triangle A C B}}=\frac{3}{5} \\
\Rightarrow S_{\triangle C O D}=\frac{3}{8} S_{\triangle A C D}=\frac{3}{8} \times \frac{3}{8} S_{\text { trapezoid } A B C D}=\frac{3}{8} \times \frac{3}{8} \times 320=45
\end{array}
$$

Therefore, the answer is: 45