10. As shown in the figure, ABCD is a trapezoid, the area of triangle ADE is 1, the area of triangle $\mathrm{ABF}$ is 9, and the area of triangle BCF is 27. What is the area of triangle $\mathrm{ACE}$?
【Analysis】From the area of triangle $\mathrm{ABF}$ being 9, and the area of triangle $\mathrm{BCF}$ being 27, we can deduce that $\mathrm{AF}: \mathrm{FC}=1: 3$.
Since $\mathrm{ABCD}$ is a trapezoid, the area of triangle $\mathrm{CDF}$ is also 9.
Given $\mathrm{AF}: \mathrm{FC}=1: 3$, the area of triangle $\mathrm{ADF}$ is 3.
Since the area of triangle $\mathrm{ADE}$ is 1, the area of triangle $\mathrm{AEF}$ is 2, so $\mathrm{DE}: \mathrm{EF}=1: 2$.
Since the area of triangle $\mathrm{CDF}$ is 9, the area of triangle $\mathrm{CEF}$ is 6.
Therefore, the area of triangle $\mathrm{ACE}$ is 8.