Answer:
The sum of the first 9 terms is
.
Explanation:
To find the sum of the first
terms of a geometric sequence use the formula

where,
is the number of terms,
is the first term and
is the common ratio.
To find the common ratio, find the ratio between a term and the term preceding it.
Given the geometric sequence
, the common ratio is

and the sum of the first 9 terms is
