'Cubits' in the Bible

Then his wife Zeresh and all his friends said to him, “Have a gallows fifty cubits high made, and in the morning ask the king to have Mordecai hanged on it; then go joyfully to the banquet with the king.” And the advice pleased Haman, so he had the gallows made.

Then Harbonah, one of the eunuchs serving the king said, “Now look, there are gallows fifty cubits (75 ft.) high standing at Haman’s house, which Haman made for Mordecai, whose good warning saved the king.” And the king said, “Hang him on it.”