Well I don't know where inequalities would come in but the third length would be solved as follows.
a^2+b^2=c^2
10^2+18^2=424
Answer;
I hope this is correct, its what I would do if I had this equation.
a^2+b^2=c^2
10^2+18^2=424
Answer;
I hope this is correct, its what I would do if I had this equation.