Hi! I'm happy to help!
To solve this, we first need to find our what could give us 1/3. WE realize that the sequence is descending, so we must be dividing. We can then, from here, multiply our top number by 1/3, because that is our end number, and could possibly work for our common ratio. From this, we can check if this fits in our equation. (dividing by 3)
243×1/3=81
81×1/3=27
27×1/3=9
9×1/3=3
3×1/3=1
1×1/3=1/3
We can check if this is the correct amount of numbers that would fit into the geometric sequence. Let's see if this fits in:
243, 81, 27, 9, 3, 1, 1/3
This does fit into our geometric sequence. Our middle terms are underlined. (missing numbers)
Our common ratio is the number we multiply the previous number by to get our next, so our common ratio is 1/3.
So, our geometric sequence is 243, 81, 27, 9, 3, 1, 1/3, our middle terms are 81, 27, 9, 3, and 1. Our common ratio is 1/3.
I hope this was helpful, keep learning!
