Well it looks like it's a clean break. I leaned against my 15X15 square ruler and it broke in half. Before I pitched it someone on Qb suggested fixing it.
1.I put it on a flat table.
2.I ran a piece of clear tape on the bottom of the ruler on one side. (half for each side)
3.I perfectly matched the ruler up and stuck the other side down to the first section.
4.I made sure the edges were all lined up correctly. (on the tape)
5.I carfully took the ruler to the table edge and opened the crack using the tape as a hinge and ran a line of super glue into the crack.
6.I immediately put the whole ruler back flat on the table to dry being careful not the touch the drying glue.
7.After drying it still works and this was several months ago.
Might be worth a try?