At that size and from pic; tadpole is Rana catesbeiana, an American Bullfrog. Here is some discussion about them: http://www.frogforum.net/care-sheet-...caresheet.html. Pretty much you will need a large tank, a single male will do OK in a 55G, a large female will require a bigger tank still. Either 75:25 or 60:40 water to dry ratio will work OK. They spend lots of time at water's edge and are very shy frogs. Planting tank or decorating it to provide retreats will help the frog to relax.

Although different scale and dry to wet ratio, this article shows some pics about how to build a split tank: Frog Forum - Building Dart Frog Terrariums / Tropical Terrarium Construction. Other options are to use a false bottom or using aquarium silicone glue and a pane of glass to build a waterproof dam. The main concept being that you need to keep the dry section substrate (either shredded coco or ABG soil if going with live plants) dry or it will become waterlogged and a bacteria breeding bog. There are many member builds in the vivarium section that illustrate the different methods. Good luck !