The line needs to be 8.06 m long
Explanation
Given that the ladder is 7 feet tall and the bottom of the slide should be 4 m away from the ladder.
The ladder,slide and the ground connecting them makes the sides of a right angled triangle with ladder as the height and ground as the base.
base=4m
height=7m
hypotenuse can be determined using pythagoras law
[tex]b^{2} +h^{2} =H^{2} \\x^{2} 4^{2}+ 7^{2}= H^{2} \\16+49=H^{2} \\H=\sqrt{65} \\=8.06 m[/tex]
