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Find a2 and a3 for the geometric sequence 4, a2, a3, 108.

User Culture
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1 Answer

5 votes

9514 1404 393

Answer:

a2 = 12

a3 = 36

Explanation:

Terms of a geometric sequence have a common ratio. If we call that ratio r, then we have ...

a2 = 4r

a3 = (a2)r = 4r^2

108 = (a3)r = 4r^3

27 = r^3 . . . . . . . . . . . divide by 4

3 = r . . . . . . . . . . cube root

__

a2 = 4(3) = 12

a3 = 12(3) = 36

User Corno
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