forty-ninth vs 49th

forty-ninth and 49th both are adjectives.

Word	Noun	Adjective	Verb	Adverb
forty-ninth	No	Yes	No	No
49th	No	Yes	No	No

As adjectives, forty-ninth and 49th are synonyms defined as:

forty-ninth and 49th: the ordinal number of forty-nine in counting order

forty-ninth (adjective)	49th (adjective)
the ordinal number of forty-nine in counting order	the ordinal number of forty-nine in counting order