Answer:
[tex]42[/tex]
Step-by-step explanation:
Remember, [tex]a^{2} + b^{2} =c^{2}[/tex]
This time, it's [tex]56^{2}+b^{2}=70^{2}[/tex]
[tex]70^2-56^2[/tex]=[tex]1764, sq rt[/tex] of [tex]1764=42[/tex]
I think it's 42