Given that $\left\{ a _ { n } \right\}$ is an arithmetic sequence with non-zero common difference, and $a _ { 1 } + a _ { 10 } = a _ { 9 }$, find $\frac { a _ { 1 } + a _ { 2 } + \cdots a _ { 9 } } { a _ { 10 } } =$ $\_\_\_\_$
$\frac { 27 } { 8 }$
Given that $\left\{ a _ { n } \right\}$ is an arithmetic sequence with non-zero common difference, and $a _ { 1 } + a _ { 10 } = a _ { 9 }$, find $\frac { a _ { 1 } + a _ { 2 } + \cdots a _ { 9 } } { a _ { 10 } } =$ $\_\_\_\_$