For the geometric sequence, find the common ratio, r.
-4, -12, 36, -108, 324, . . .
A)-16
B)-3
C)36
D)3

Question

Quizplus · Accepted Answer

The common ratio, $r$, in a geometric sequence is found by dividing any term by the term preceding it. For this sequence, dividing the second term (-12) by the first term (4) gives $-12 / 4 = -3$, or dividing the third term (36) by the second term (-12) gives $36 / -12 = -3$. Thus, the common ratio is -3.

For the Geometric Sequence, Find the Common Ratio, R