how to backup iPad

I have an iPad 2, an iPad 3. I have an iMac 21.5" and a time Capsule on local wifi personal network. Time Machine backs up my iMac to Time Capsule. How can I back up my iPads?

 

You can backup your iPads using iTunes on your iMac, or iCloud: http://support.apple.com/kb/HT5262

 

You can backup your iPad in iTunes or iCloud. If you backup you files in Cloud, you can get 5GB are free. In this situation, you can make and use backups from anywhere with Wi-Fi. If you stores backups on your Mac or PC by iTunes, you can make and use backups from your Mac or PC.