HELP! Please answer fast How many terms are in the geometric series 0.4 + 1.2 + 3.6 + ... + 7,873.2?

10 terms. I think you should check the explanation :)

Step-by-step explanation:

0.4 + 1.2 + 3.6 + ... + 7,873.2?

So I figured that you have to multiply the terms by three to get the next term.

0.4 * 3 = 1.2

1.2 * 3 = 3.6

But, I know it will takes us a really long time to get to 7,873.2, so what I will do is jump 3 sequences.

So if I multiply by 3 to get the next term, I'll multiply by 9 to get the next two terms because 3 * 3 is 9.

So to jump three times, I will multiply by 27 to get the next three terms because 3 * 3 * 3 is 27.

0.4 + 1.2 + 3.6 + ...

3.6 * 27 = 97.2

0.4 + 1.2 + 3.6 + ..., ..., 97.2, ...

97.2 * 27 = 2624.4

0.4 + 1.2 + 3.6 + ..., ..., 97.2, ..., ..., 2624.4, ...

Since we are getting close, I'm going to go back to multiply by 3.

2624.3 * 3 = 7873.2

0.4 + 1.2 + 3.6 + ..., ..., 97.2, ..., ..., 2624.4, 7873.2

Now that we have reached 7873.2, we will now count the terms (count the sets of three dots as terms too).

There are 10 terms in the geometric sequence.

b is the answer that makes most sense

step-by-step explanation: