Quick Geometric Series Question.

I dont understand how to get r in the equation for finding the sum.

sum = a/(1-r)

I understand how to get a though.

Question

Quick Geometric Series Question.

I dont understand how to get r in the equation for finding the sum.

sum = a/(1-r)

I understand how to get a though.

mathslover · Answer

sum * (1-r) = a

1-r =  a/(sum) 

r = 1- ( a/ sum )

anonymous · Answer

I mean without knowing the sum. For example, ive attached a problem.
a = 10/11

anonymous · Answer

r is your common ratio.

anonymous · Answer

i know i just dont understand how to get that. I can usually guess it but i would like to know how to find it.

anonymous · Answer

You know, if there is a way to find r without knowing the sum, I do not know it. I hope someone else does though because now I'm curious as well. I'm sorry, I wish I could help!

anonymous · Answer

if some one could just help me get r in this problem that would be fine.