protract vs prolong

protract and prolong both are verbs.

Word	Noun	Adjective	Verb	Adverb
protract	No	No	Yes	No
prolong	No	No	Yes	No

As verbs, protract and prolong are synonyms defined as:

Other synonyms of protract include draw out, extend.

protract (verb)	prolong (verb)
lengthen in time; cause to be or last longer	lengthen in time; cause to be or last longer
	lengthen or extend in duration or space