Okay so first some definitions
Geometric sequence and common ratio. A geometric sequence a sequence where the next number is the previous number multiplied by the same number as in the whole seequence a.k.a a common ratio.
equation:
150+c120+c=120+c60+c=x
okay so we want to find what x is.
solve: find common denominators
9000+210c+c2=14400+240c+c2
30c=−5400 , soc=−180.
Now we get x = 1/2 so yeah
TO CHECK:
plug x back in to the equations to that it is correct! I hope you got it so the common ratio is 1/2