We are gonna apply the Pythagorean theorem
h = 9
a = 4
[tex]\begin{gathered} h^2=a^2+b^2 \\ b=\sqrt[]{h^2-a^2} \\ b=\sqrt[]{9^2-4^2} \\ b=\sqrt[]{81-16} \\ b=\sqrt[]{65} \\ b=8.062 \end{gathered}[/tex]Now we are gonna calculate all the values
[tex]\begin{gathered} a+b>c \\ 9+4>c \\ 13>c \end{gathered}[/tex]Triangle Inequality |4-9|
[tex]\begin{gathered} |-5|The answers would bec. 7 feet
d. 12 feet