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

Answer 1

4th term / second term  = a1r^3 / a1r = r^2

so r^2  = 45/4 / 20 = 45/80  = 9/16

so r = sqrt 9/16  = 3/4  answer