How do you open RAR files on a Mac?

To open RAR files on a Mac you will need an expander such as RAR Expander software (See links below).

You can use free, open source Zipeg program from http://zipeg.com (or see link below)

Zipeg opens RAR, ZIP and many other file formats and works on both Macintosh and Windows. It also supports filenames in national alphabets and provides quick pick inside the RAR and ZIP files if they contains pictures or photographs.

Zipeg allows users to extract all or individually selected files and folders from archives.