Verified Answer :

to find the common ratio, divide the second term by the first term.
-86/-172 = 1/2

so 1/2 is ur common ratio

Answer:

common ratio between successive terms in the sequence is \(\frac{1}{2}\)

Step-by-step explanation:

Common ratio(r) defined as the ratio of a term to the previous term.

also common ratio term is constant.

Given the sequence:

-172 -86 -43 -21.5

⇒\(a_1 = -172\)

\(a_2 = -86\)

\(a_3 = -43\)

\(a_4 = -21.5\)

Then by definition of common ratio:

\(r = \frac{a_2}{a_1}=\frac{a_3}{a_2}=\frac{a_4}{a_3}\)

Substitute the given values we have;

\(r = \frac{-86}{-172} = \frac{-43}{-86}=\frac{-21.5}{-43}\)

⇒\(r = \frac{1}{2}\)

Therefore,  the common ratio between successive terms in the sequence is \(\frac{1}{2}\)