i. 32 = 9, 42 = 16, 52 = 25
Now, 9 + 16 = 25
∴ 32 + 42 = 52
∴ 3, 4 and 5 is a Pythagorean triplet.
ii. 22 = 4, 42 = 16, 52 = 25
But, 4 + 16 ≠ 25
∴ 22 + 42 ≠ 52
∴ 2, 4 and 5 is not a Pythagorean triplet.
iii. 42 = 16, 52 = 25, 62 = 36
But 16 + 25 ≠ 36
∴ 42 + 52 ≠ 62
∴ 4, 5 and 6 is not a Pythagorean triplet.