Step-by-step explanation:
[tex]a^{2} + b ^{2} = c^{2}[/tex]
[tex][ (3a)^{3} ]^{2}[/tex] + [tex][ (4a)^{3} ]^{2} = C^{2}[/tex]
I'm assuming the length was [tex](3a)^{3}[/tex], not 3[tex]a^{3}[/tex].
It was difficult to tell in your question.
[tex](3a)^{6} +(4a)^{6} = C^{2}[/tex]
729[tex]a^{6}[/tex] + 4096[tex]a^{6} = C^{2}[/tex]
4825[tex]a^{6} = c^{2}[/tex]
Take the square root of both sides.
69.4622[tex]a^{3}[/tex] ≈ c
