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.

just get this app called photo math it should be able to do those

but there’s no any figure there!