Which of these four sets of side lengths will form a right triangle?

Set 1
6 cm, 7 cm, StartRoot 12 EndRoot cm

Set 2
8 in., StartRoot 29 EndRoot in., StartRoot 35 EndRoot in.

Set 3
StartRoot 3 EndRoot mm, 4 mm, StartRoot 5 EndRoot mm

Set 4
9 ft, StartRoot 26 EndRoot ft, 6 ft