Answer:
9 terms
Explanation:
I could be wrong and I apolgize if I am, but I multiplied 243 by 3 as I look at the other numbers noticing that they have been multiplied by 3 each and did it until I got 6561.
There are already 6 terms and I multiplied 3 by each number only 3 more times and ended up with 6561.
6 + 3 = 9 terms.