117, 23.4, 4.68, … 23.4/117 = 234/1170 = 0.2 4.68/23.4 = 468/2340 = 0.2 So it's a geometric sequence with a1 = 117 and r = 0.2 an = a1rn-1 an = 117(0.2)n-1 Edwin