The Collaborative International Dictionary of English v.0.48:

Deducible \De*du"ci*ble\, a.
   1. Capable of being deduced or inferred; derivable by
      reasoning, as a result or consequence.
      [1913 Webster]

            All properties of a triangle depend on, and are
            deducible from, the complex idea of three lines
            including a space.                    --Locke.
      [1913 Webster]

   2. Capable of being brought down. [Obs.]
      [1913 Webster]

            As if God [were] deducible to human imbecility.
                                                  --State Trials
                                                  (1649).
      [1913 Webster]

WordNet (r) 3.0 (2006):

deducible
    adj 1: capable of being deduced