You can
put this solution on YOUR website!
In a geometric series, finite or infinite, the

is the multiplier used to get each succeeding term. Or, you can think of it as any term divided by the previous one.
For example, in the series you have
1.1+0.11+0.011+.............the common ratio is
If an infinite geometric series has a ratio whose absolute value is less than

, and so has a

, the formula is
where

just stands for the sum of an infinite series,

is the first term, and

is the common ratio.
in your case: