In a geometric series, The consecutive terms are related by a common ratio, r
r = second term/first term = third ter/second term .......
From the sequence, it means that
r = - 21/- 6 = - 73.5/- 21 = - 257.25/- 73.5 = 3.5
Thus, the next term after 257.25 would be
-257.25 * 3.5
= -900.375
The next term is -900.375
