Answer:
[tex]\Large\text{The hypotenuse is}\ \sqrt{41}\ ft\approx6.4\ ft[/tex]
Step-by-step explanation:
[tex]\text{Use the Pythagorean theorem:}[/tex]
[tex]a^2+b^2=c^2[/tex]
[tex]\text{a, b - legs}\\\text{c - hypotenuse}[/tex]
[tex]\text{We have the legs 4ft and 5ft. Substitute:}[/tex]
[tex]c^2=4^2+5^2\\\\c^2=16+25\\\\c^2=41\to c=\sqrt{41}[/tex]