Answer
See below.
Work Step by Step
The nth term of an arithmetic sequence can be obtained by the following formula: $a_n=a_1+(n-1)d$, where $a_1$ is the first term and $d$ is the common difference.
Hence here: $d=\sqrt2,n=9,a_1=\sqrt2,a_{9}=\sqrt2+(9-1)\sqrt2=9\sqrt2$
