Translation:How tall are you?
Well there's nothing relevant before 2015, as a search of klingonska.org shows. The word 'ar does not appear in paq'batlh. I have no record of any announcement of canon regarding the word 'ar in my mailing list archive (except for when Okrand, in 1998, introduced us to 'arlogh). My records of other sources are not perfect, but show no sign of any use of 'ar.
If there's no canon to support using 'ar by itself, I suggest that such use is incorrect and recommend changing this sentence to 'uj 'ar bo'ab.