Which of these four sets of side lengths will form a right triangle? Set 1 10 cm, 26 cm, 24 cm Set 2 4 in., 2 in., 6 in. Set 3 14 mm, 13 mm, 15 mm Set 4 10 ft, 30 ft, 20 ft Set 1 Set 2 Set 3 Set 4

The answer is Set 1, this is because you can do Pythagoras' theorem and say that 10^2 + 24^2 must equal 26^2, so:

100 + 576 = 676

√676 = 26

And therefore Set 1 is a right-angled triangle because Pythagoras' theorem only works on right-angled triangles