Find S9, the sum of the geometric series to the 9th term, in which a3=3.645 and a8=15

The sum of the first nine terms of the sequence is 74.44.

Step-by-step explanation:

Geometric sequence concepts:

The nth term of a geometric sequence is given by the following equation.

In which r is the common ratio.

This can be expanded for the nth term in the following way:

In which is the first term.

Or even:

The sum of the first n terms of a geometric sequence is given by:

Finding the common ratio:

Finding the first term:

Sum of the first nine terms:

The sum of the first nine terms of the sequence is 74.44.

6.5

step-by-step explanation:

you said it was in the question

~courtney