X = 65(7)
X = 455
Marla did 455 sit-ups in a week
Answer:
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:






![r = \sqrt[5]{\frac{15}{3.645}}](https://tex.z-dn.net/?f=r%20%3D%20%5Csqrt%5B5%5D%7B%5Cfrac%7B15%7D%7B3.645%7D%7D)

Finding the first term:




Sum of the first nine terms:

The sum of the first nine terms of the sequence is 74.44.
Answer:
i am pretty sure yes
Step-by-step explanation: