\(153.8\)

\begin{align}
&a=4,\; r=\frac{6}{4}=1.5 \\
&\begin{aligned}
T_{n}&=a r^{n-1} \\
T_{10}&=4 \times(1.5)^{9} \\
&= 153.8
\end{aligned}
\end{align}