What is the sum of the geometric sequence 1, 3, 9, … if there are 12 terms?

292,524

265,720

139,968

104,976

The sum of the given geometric series if there are 12 terms is:

                                265,720

Step-by-step explanation:

We are given a geometric sequence as:

1,3,9,.....

This means that the common ratio(r) of the sequence is:  3

Since each term is increasing by a multiple of '3'

Also, sum of an finite geometric series with n terms is given by:

where n is the number of terms whose sum is calculated and a is the first term of the sequence.

We have n=12, a=1 and r=3

Hence, the sum is:

         Hence, the sum is:  265,720