What are the next four terms in the following geometric sequence?
5, 15, 45,…
Solution:-
First we are find common ratio 
= 3
In geometric sequence we have to find the next number by multiply last number to common ratio.
45*3 = 135
135 * 3 = 405
405*3 = 1215
1215*3 = 3645
So the next four terms are 135, 405, 1215, 3645