Question

Find the missing terms of the geometric sequence 480, ___, ___, ___, 12.288, …. (hint: the geometric mean of the first and fifth terms is the third term.)

Answer 1

To solve this problem  you must apply the proccedure shown below:
 1. You have:
 480r^(5-1)=12.288
 480r^4=12.288
 r^4=12.288/480
 r=(12.288/480)^(1/4)
 r=0.4
 2. Now, multiply r=0.4 to each term, as below:
 480x0.4=192
 192x0.4=76.8
 76.8x0.4=30.72
 30.72x0.4=12.288
 Therefore, as you can see, the answer is: 192,76.8,30.72