What is the minimum length ladder that a worker needs to access a landing nine feet above the adjacent floor?

 minimum length ladder that a worker needs to access a landing nine feet above the adjacent floor is 12 feet  

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

Cross multiply:

x = 9/4  

x = 2.5 feet away from the base

Using the Pythagoras Theorem:  

a² + b² = c²  

place the values (a = 2.5, b = 9):  

2.5² + 9² = c²  

= 9.34 feet  

Now, the length should always be more than the height:  

9.34 + 2 = 11.34  

A minimum of 11.34 feet. As a result, rounding off would result in a 12 foot ladder.

since proposition states that a number is greater than 25, if is true then the number must actually be greater than 25.

this implies that all possible options, except 24, can be accepted

the answer is b.)

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