What are the minimum dimensions for a sukkah?

A kosher sukkah must have at least 3 walls, and each wall must have a minimum length of 28 inches (7 tefachim x 7 tefachim)3. The walls of the sukkah must extend at least 40 inches high4, and the walls may not be suspended more than 9 inches above the ground5 (this is a common problem with fabric sukkahs).
_____________
3. Shulchan Aruch (O.C. 634:1)
4. Shulchan Aruch (O.C. 633:8)
5. Shulchan Aruch (O.C. 630:9)