Answer:
62.8 inches
Step-by-step explanation:
c = πd
c = 3.14 * 20
c = 62.8 inches
<h3>
Answer: -6, 7, -8</h3>
Start with the sequence {1, 2, 3, 4, 5, 6, 7, 8, ...}
Then change the sign of every other term so you'll have the first term positive, the second term negative, and so on.
That updates to {1, -2, 3, -4, 5, -6, 7, -8, ...}
Every odd term (1,3,5,..) is positive while every even term (-2,-4,-6) is negative.
Just add up all the sides
It's 
for <em>n</em> = 1, 2, 3, …
