Let's begin by listing out the information given to us:
[tex]\begin{gathered} a^2+b^2=c^2 \\ a=9,b=40 \\ 9^2+40^2=c^2 \\ 81+1600=c^2 \\ 1681=c^2\Rightarrow c^2=1681 \\ c=\sqrt[]{1681}=41 \\ c=41 \end{gathered}[/tex]
Therefore, the answer in the yellow colour is the correct answer
