Answer:
90
Step-by-step explanation:
To find s4 we find sum of values when n=1,n=2,n=3,n=4
given expression is 
n=1 , plug in 1 for n

n=2

n=3

n=4

Sum of all 4 terms = 6+12+24+48=90
Answer:
7:36
Step-by-step explanation:
Hello,
Please, see the attached files.
Thanks.
It would be circular since it was cut from a cylindrical log.
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