Answer:
Step-by-step explanation:
x = 136/2 = 68°
Answer:D) 84
Step-by-step explanation:
The given sequence is
a₁, a₂, ...,
![a_{n}](https://tex.z-dn.net/?f=%20a_%7Bn%7D%20)
Because the given sequence is an arithmetic progression (AP), the equation satisfied is
![a_{n}=a_{1}+(n-1)d](https://tex.z-dn.net/?f=%20a_%7Bn%7D%3Da_%7B1%7D%2B%28n-1%29d%20)
where
d = the common difference.
The common difference may be determined as
d = a₂ - a₁
The common difference is the difference between successive terms, therefore
d = a₃ - a₂ = a₄ - a₃, and so on..
The sum of the first n terms is
![S_{n}= \frac{n}{2} (a_{1}+a_{n})](https://tex.z-dn.net/?f=S_%7Bn%7D%3D%20%5Cfrac%7Bn%7D%7B2%7D%20%28a_%7B1%7D%2Ba_%7Bn%7D%29)
Example:
For the arithmetic sequence
1,3,5, ...,
the common difference is d= 3 - 1 = 2.
The n-th term is
![a_{n}=1+2(n-1)](https://tex.z-dn.net/?f=a_%7Bn%7D%3D1%2B2%28n-1%29)
For example, the 10-term is
a₁₀ = 1 + (10-1)*2 = 19
Th sum of th first 10 terms is
S₁₀ = (10/2)*(1 + 19) = 100
Basically you multiply like normal and then add in the decimal point (to figure out where it goes count how many numbers are behind the decimal (in this case 2) and then count that many places from the right into your answer and that's where it goes). So here 374 x22 =8228 but when you add in the decimal you get 82.28 :)