Based on the given numbers, the first term of the sequence is 8. Now, find the common ratio r.
$$ r=\frac{4}{8}=\frac{2}{4}=\frac{1}{2} $$
So, the ninth term of the sequence can be found using the formula written below.
$$ a_n=a_1\times r^{n-1},a_1=8,r=\frac{1}{2} $$
Therefore,
$$ a_9=8\times\left(\frac{1}{2}\right)^{9-1}=8\times\left(\frac{1}{2}\right)^8, $$
$$ a_9=\frac{1}{32} $$