interpolate vs extrapolate

interpolate and extrapolate both are verbs.

Word	Noun	Adjective	Verb	Adverb
interpolate	No	No	Yes	No
extrapolate	No	No	Yes	No

As verbs, interpolate and extrapolate are synonyms defined as:

interpolate and extrapolate: estimate the value of something based on known values

interpolate (verb)	extrapolate (verb)
insert words into texts, often falsifying it thereby	estimate the value of something based on known values
estimate the value of something based on known values	gain knowledge of (an area not known or experienced) by extrapolating
	draw from specific cases for more general cases