עֶ֥שֶׂר אַמּ֖וֹת אֹ֣רֶךְ הַקָּ֑רֶשׁ וְאַמָּה֙ וַחֲצִ֣י הָֽאַמָּ֔ה רֹ֖חַב הַקֶּ֥רֶשׁ הָאֶחָֽד׃
Ten cubits shall be the length of a board, and a cubit and a half the breadth of each board.
Rashi on Exodus
עשר אמות ארך הקדש TEN CUBITS SHALL BE THE LENGTH OF A BOARD — This tells us that the height of the Tabernacle was ten cubits (since the boards were standing vertically).
Rashi on Exodus
ואמה וחצי האמה רחב AND A CUBIT AND A HALF SHALL BE THE BREADTH — This teaches us that the length of the Tabernacle corresponding to the twenty boards which were on the north and on the south was 30 cubits from east to west.