I am a novice at this. My iMac is connected to the internet with an ethernet cable. No wi-fi in the house otherwise. Since the iMac has a wi-fi system I was thinking that I could connect to the iMac with the iPad and use it around the house. I do not have a wireless router but am thinking that in order to do what I want I will need one.
Thanks for the information - your iMac has a Wi-Fi radio that can connect to a wireless network if available which is not true in your house; thus, the iPad cannot really connect to your iMac in that fashion.
I'm assuming that you have an ISP (Internet Service Provider) who is bringing in a broadband connection (likely cable or possibly DSL, Digital Subscriber Line) to a modem and an ethernet cable connects the modem to your iMac - correct? If so, you need to purchase a 'wireless' router (or contact your ISP to see if they offer a 'combo' device, i.e. a modem + router which they would likely setup) and attach it between your modem & your computer, and then setup the Wi-Fi network - your iPad will then be able to have a Wi-Fi connection.
Since your needs seem to be simple at this point (i.e. don't know how many other Wi-Fi devices are in your house, but as an example, in my home, wife and I have iPads; she has an iPhone & I an iPod, all using Wi-Fi; in addition, my HDTV & Blu-Ray player are Wi-Fi compatible; and finally we have two Roku devices that work on Wi-Fi), I would suggest looking at Apple's AirPort Express
router, but many other brands and models exist, including Apple's AirPort Extreme which I use. Hope this helps. Dave