Answer:
a4 = 189
Step-by-step explanation:
Geometric sequence:
In a geometric sequence, the quotient r between consecutive terms is always the same.
The nth term of the sequence is given by:
[tex]a_n = a_1*r^{n-1}[/tex]
In which [tex]a_1[/tex] is the first term.
In this question:
[tex]a_1 = 7, r = 3[/tex]
The fourth term is:
[tex]a_4 = 7*3^3 = 189[/tex]
So
a4 = 189
