We know that
see the picture to better understand the problem
in the right triangle ABC
Applying the Pythagoras Theorem
AB²=BC²+AC²-------> BC²=AB²-AC²
AB=8 ft
AC=4 ft
BC²=8²-4²-----> BC²=48--------> BC=√48-------> BC=6.93 ft
the answer is
6.93 ft
see the picture to better understand the problem
in the right triangle ABC
Applying the Pythagoras Theorem
AB²=BC²+AC²-------> BC²=AB²-AC²
AB=8 ft
AC=4 ft
BC²=8²-4²-----> BC²=48--------> BC=√48-------> BC=6.93 ft
the answer is
6.93 ft