Answer:
length of the ladder should be 16 feet.
Explanation:
In the figure attached,
B is the window at 12 feet from the ground.
Building AB is 2 feet away from the fence DE.
Ladder AC is placed 8 feet away from the fence at a point C.
We apply Pythagoras theorem to calculate the length of the ladder.
AC² = AB² + BC²
AC =

=

=

= 15.62
≈ 16 feet
Therefore, length of the ladder should be 16 feet.