In order to determine what side lengths form a right triangle, use the Pythgoras theorem to verify the following:
h² = c1² + c2²
Where h is the longer side of the triangle.
For sides 1,1,2:
1² + 1² = 1 + 1 ≠ 2²
sides 6,10,8:
6² + 8² = 10²
Triangle with side lengths 6, 8 and 10 will form a right triangle.