Find the partial sum S_n for a geometric series such that a_{4} = 216, a_{9} = 52488, and n = 10.

Answer 1

I assume that a_{n} ios the nth term of the series.

The ratio of successive terms is 3, since
(52488/216)^(1/5) = 3

a_{n} = (216/81)* 3^n

Add up the first 10 terms for the partial sum S_n