How Do You Measure Rice ?

I had an interesting experience the other day in a grocery store which evoked memories of my childhood. I was looking for some black sticky rice. The sales clerk asked if I needed any help. She was Asian in a non-Asian grocey store and we were in the Asian section. She found it for me and I asked her what the ratio was between rice and water for cooking. She looked at me perplexed and shrugged, "I don't know, I've always just used my finger up to the first line". Immediately we connected. My parents did that all the time when they cooked rice and for some reason, it's kind of faded away from me over the years.