Triangle #1
c = 5.000
Triangle #2
a = 6.708
Triangle #3
Impossible.
Triangle #4
c = 17.263
Triangle #5
c = 2036.666
Triangle #6
c = 1.414
Triangle #7
a = 4.000
Triangle #8
a = 237.167
Triangle #9
Impossible.
Triangle #10
b = 5.657
Triangle #11
b = 309.839
Triangle #12
Impossible.