ex·trap·o·late 
(ĭk-străpə-lāt′)
(ĭk-străpə-lāt′)v. ex·trap·o·lat·ed, ex·trap·o·lat·ing, ex·trap·o·lates
v.tr.
1. To infer or estimate by extending or projecting known information.
2. Mathematics To estimate (a value of a variable outside a known range) from values within a known range by assuming that the estimated value follows logically from the known values.
v.intr.
To engage in the process of extrapolating.
[EXTRA- + (INTER)POLATE.]
ex·trap′o·lation n.
ex·trapo·la′tive adj.
ex·trapo·la′tor n.