B(cone)=B(pyramid)=r²π
V(pyramid)=1/3 * B * H = 1/3 * r² π * 3 r ( 3 will cancel out )= r³ π
Answer: r³ π
7.67 is your answer. hope this helps, let me know if you need more help
Answer:

Step-by-step explanation:
The explicit formula for a geometric sequence:

- n-th term
- first term
- common ratio

We have

The common ratio:

<h2>It's not a geometric sequence.</h2>
If
then the common ratio is 
Put to the explicit formula:

Put
and solve for <em>n </em>:


I think the answer is either 3/49 or about 0.061
hope this helps.