Answer :
[tex]\text{H}^2=a^2+b^2[/tex]
Where
H = Hypotenuse (side oposite to the angle of 90 °)
a and b = legs (other sides of triangule)
[tex]\begin{gathered} \text{H}^2=a^2+b^2 \\ 13^2=12^2+b^2 \\ 169=144+b^2 \\ 25=b^2 \\ b=\sqrt[]{25} \\ b=5 \end{gathered}[/tex]QUESTION 2
H = 13 cm
a = 9 cm
[tex]\begin{gathered} \text{H}^2=a^2+b^2 \\ 13^2=9^2+b^2 \\ 169=81+b^2 \\ 169-81=b^2 \\ 88=b^2 \\ b=\sqrt[]{88} \\ b=9.40 \end{gathered}[/tex]