How long was the flying scroll that Zechariah saw?

Answer: 20 cubits

Zechariah saw a flying scroll twenty cubits long and ten cubits wide, a curse going out over the whole land.

“Again I lifted up my eyes and saw before me a flying scroll. “What do you see?” asked the angel. “I see a flying scroll,” I replied, “twenty cubits long and ten cubits wide.””— Zechariah 5:1-2 (BSB)