Answer: A 12 foot ladder would be the minimum length that is going to be required by a worker to access a landing nine feet above the adjacent floor
So with the standard terms the ladder should be at least 1 unit away for 4 feet of height so, keeping in mind the unitary method:
Height Away from base
4 1
9 x
The amount a 9 feet ladder should be away is:
x = 2.5 feet away from the base
Using the Pythagoras Theorem:
a² + b² = c²
place the values for the right triangle (a = 2.5, b = 9):
2.5² + 9² = c²
= 9.34 feet
Now, we know that the length of the ladder should always be more than the height you are trying to reach:
9.34 + 2 = 11.34
The minimum height of the ladder should be 11.34 feet. As a result, rounding off would result in a 12 foot ladder.