A child theme resides in its own directory in wp-content/themes. The scheme below shows the location of a child theme along with its parent theme (Twenty Twelve) in a typical WordPress directory structure:
1More
Hybrid WordPress Theme Framework - 1 views
1More
JungleJar | Looking at Wordpress Custom Fields and Images Further - 6 views
1More
WordPress CMS Development - A Power Packed Solution - 3 views
1More