Respuesta :

manuelperezpinp1dgij
If you divide each number by the previous one, you get:

-86 / -172 = 1/2
-43 / -86 = 1/2
-21.5 / -43 = 1/2

The common ratio is 1/2 = 0.5
KADR257
The common ratio of each one is 1/2 or .5
If ya need any more help let me know.
Brainliest?