Answer:
[tex]\large\boxed{\sqrt{65}\ ft}[/tex]
Step-by-step explanation:
Use the Pythagorean theorem:
[tex]leg^2+leg^2=hypotenuse^2[/tex]
We have
[tex]leg=4ft,\ leg=7ft,\ hypotenuse=AB[/tex]
Substitute:
[tex]AB^2=4^2+7^2\\\\AB^2=16+49\\\\AB^2=65\to AB=\sqrt{65}[/tex]
