Question

The second term in a geometric sequence is 20. The fourth term in the same sequence is 45/4, or 11.25. What is the common ratio in this sequence?

Answer 1

0.75

Explanation:

Answer 2

We use equations for geometric sequence. We do as follows:

a(n) = a(1) r^(n-1)
20 = ar^(2-1)
20 = ar
a = 20/r

11.25= ar^(4-1)
11.25 = ar^3
11.25 = (20/r)r^3
r = 0.75

Hope this answers the question. Have a nice day.