Argument Let the common ratio be r Let each term be numbered by t
r = t2/t1 r = 96 / 128 = 0.75
Try it again r = t3/t2 r = 72 / 96 r = 0.75
Conclusion the common ratio for the given series is 0.75
Remark. Any term can be calculated from the following formula. tn = 128(0.75)^(n-1) So if you want the 4th term tn = 128(0.75)^(4 -1) tn = 128(0.75)^3 tn = 128 * 0.421875 tn = 54 which is exactly what it should be.
