Exodus 26:16 KJV
Ten cubits shall be the length of a board, and a cubit and a half shall be the breadth of one board.
Exodus 26:16, King James Version
In context
15 And thou shalt make boards for the tabernacle of shittim wood standing up.
16 Ten cubits shall be the length of a board, and a cubit and a half shall be the breadth of one board.
17 Two tenons shall there be in one board, set in order one against another: thus shalt thou make for all the boards of the tabernacle.