My first thought was:
1) IF you have enough of the triangle fabric - to cut new triangles so that the long edge is on the outside.
My second though was - which will be contrary to just about everything I've read so far:
Remove the triangles - soak them in hot water for about 20 minutes - swish them around a few times - to help the fabric get back to whatever it's 'normal' was and to remove the starch. Dry them on a towel or over a towel bar. Then press them gently 'on the grain' and see what they look like. They may have gotten stretched way out of shape with all the handling.
For an experiment, you could trace around the pieces to see what they look like before you dunk them and then compare the 'after' to it.