Given that the length of each curtain was twenty-eight Amos, and that the curtains were spread across the width of the Mishkan, how much of the north and south (outer) walls remained uncovered?
Rashi: Ten Amos covered the inside of the Mishkan, two Amos, the width of the two boards (on top, one on each side), leaving sixteen Amos to cover the two walls, eight on each side - and two Amos (one Amah plank, and one, socket) uncovered on each side.
Rashbam (in Pasuk 9) and Riva (in Pasuk 5),: According to the opinion that the boards were only a finger-breadth wide at the top 1 , ten Amos covered the interior width of the Mishkan, leaving nine Amos to cover each side wall, leaving only one Amah (socket) uncovered on each side. 2
Hadar Zekenim (in Pasuk 17): The Kerashim were straight towards the interior [of the Mishkan], and tapered off on the outside, because otherwise, the Mishkan would have been more than ten Amos wide, and the curtains would only have reached until the sockets! See Torah Temimah, citing Shabbos, 95b and note 10.
The calculation ignores the finger-breadth, and also that the length of sloped boards is a bit more than their height (ten Amos). It was a miracle that heavy curtains over a large opening did not sag in the middle, and they fitted flush in the corners. (If a tablecloth is longer and wider than the table it covers, the excess sticks out. The area of ten curtains, each tjirty by four Amos, is one thousand two hundred square Amos, about huncred times more than the total area of the three sides and top of the Mishkan that they covered!) Perhaps it was also a miracle that the curtains reached until the sockets. Or, the curtains were twenty-eight Amos long when woven, but when they hung on the Mishkan, they stretched a little due to their own weight - PF).
Why does the the Torah insert the (otherwise superfluous) word "Orech ha'Yeri'ah ha'Achas"?
