172 is external-braced supported, so not cantilevered. But that's hair-splitting. C-177/RG is an more clear example of a cantilevered wing.
On more complex structures the interaction of wing spars and wingboxes make the definition a little fuzzy but I could still venture and speak generally on the type of wing structure, as perceived externally...i.e. anything without external bracing can be considered cantilever in GENERAL. Hope that helps man.