Solution :
Let a be the first term and r the common ratio of the given G.P. Then,
\(a_4\) = 54 and \(a_9\) = 13122
\(\implies\) \(ar^3\) = 54 and \(ar^8\) = 13122
\(\implies\) \(ar^8\over ar^3\) = \(13122\over 54\) \(\implies\) \(r^5\) = 245 \(\implies\) r = 3
Putting r = 3 in \(ar^3\) = 54,
we get a = 2.
Hence, the given G.P is 2, 6, 18, 54, ….
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