Circle Area = PI * radius^2
radius = 2.1
Circle Area = 3.14 * 2.1^2
Circle Area =
<span>
<span>
<span>
13.8
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Answer:
Sorry sis don't know the answer
Answer:
![\displaystyle S_{8}=6560](https://tex.z-dn.net/?f=%5Cdisplaystyle%20S_%7B8%7D%3D6560)
Step-by-step explanation:
We have the geometric sequence:
2, 6, 18, 54 ...
And we want to find S8, or the sum of the first eight terms.
The sum of a geometric series is given by:
![\displaystyle S=\frac{a(r^n-1)}{r-1}](https://tex.z-dn.net/?f=%5Cdisplaystyle%20S%3D%5Cfrac%7Ba%28r%5En-1%29%7D%7Br-1%7D)
Where <em>n</em> is the number of terms, <em>a</em> is the first term, and <em>r</em> is the common ratio.
From our sequence, we can see that the first term <em>a</em> is 2.
The common ratio is 3 as each subsequent term is thrice the previous term.
And the number of terms <em>n</em> is 8.
Substitute:
![\displaystyle S_8=\frac{2((3)^{8}-1)}{(3)-1}](https://tex.z-dn.net/?f=%5Cdisplaystyle%20S_8%3D%5Cfrac%7B2%28%283%29%5E%7B8%7D-1%29%7D%7B%283%29-1%7D)
And evaluate. Hence:
![\displaystyle S_8=6560](https://tex.z-dn.net/?f=%5Cdisplaystyle%20S_8%3D6560)
The sum of the first eight terms is 6560.
Answer:
The answer is 1.79 × 10-3