They are the set of lengths of a right triangle if they satisfy the pythagorean theorem:
[tex]\begin{gathered} c^2=a^2+b^2 \\ Where \\ c>a \\ c>b \end{gathered}[/tex]so:
[tex]\begin{gathered} 42^2=24^2+33^2 \\ 1764=1665 \\ False \\ 1764\ne1665 \end{gathered}[/tex]the set of lengths which are not side of a right triangles is:
A 24, 33, 42
