丈は四寸（よき）もございましたか？ とはどういう意味ですか?

質問を翻訳

寸 is a unit of length that has been used in Japan since ancient times, usually read as "すん". 1 寸 = about 30 mm. It is mainly only in ancient literature that the word "寸" is read as "き". Since "藪の中" is set in the Heian period, I think that's why the "すん" is written with furigana "き". In modern times, everyone only reads "すん".

The word "丈" means length, and in this case it refers to height. In the story, 旅法師（The traveling priest） was asked by 検非違使（a police officer） how tall he thought a man was. The traveling priest replied, "(Did you say) Was he four 寸 tall?" because the narration in this scene is not conversational but monologue, Akutagawa has the priest repeat the question so that the reader can understand what the inspector has asked.

In other words, the inspector asks the priest, "Was the man's height about four 寸? By the way, 4寸 = 120mm, which is naturally too short. This is because the height of a person is usually between 150 cm and 180 cm, where 150 cm = 5 尺 and 180 cm = 6 尺 (10寸 = 1尺 = 300 mm), and it was customary to omit the 5 尺 part when referring to a person's height, and only refer to the n寸 part(of 5尺 + n尺).
Therefore, the question, "Was the man's height about 4寸? "would mean, "Was the man's height about 5尺4 寸 (≒162cm)? .