Answers

2016-07-27T20:53:32+08:00
Just use the geometric mean formula to get the ratio of the sequence.
an = a1 * r^n-1
108 = 4 * r^4-1
108/4 = r^3
27 = r^3
r=3
then use the geometric formula for getting the last term (a8) term
make 108 to be your first term
a8 = 108 * 3^5-1
a8 = 108 * 3^4
a8 = 108 * 81
a8 = 8748
hope it helps.
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