You can put this solution on YOUR website! Note: is the 5th partial sum of the geometric sequence. To find the 5th partial sum, we use the value (since we start at ) and use the formula
Since we know that , this means that
Replace the left side with 92.3125
Plug in and
Combine like terms.
Raise 1.5 to the 5th power to get 7.59375
Combine like terms.
Divide
Divide both sides by 13.1875 to isolate "a"
Divide
So we find that (which is the first term)
Now to find , we will use
Start with the right side of the formula
Plug in , , and
Combine like terms.
Raise 1.5 to the 10th power to get 57.665 (this is approximate)
Combine like terms.
Multiply
Divide
So the tenth partial sum is approximately . This means that