Question 20744
Q:- A ladder 13 ft long leans against a wall. The bottom of the ladder is 5 ft from the wall. How much would the lower end of the ladder have to be pulled away so that the top end would be pulled down by 2 ft?
Solution:

Just see the ladder against wall as a right angled triangle

Length of Ladder = 13m
Bottem of ladder  = 5m
So Top end of ladder = Squr(13*13 - 5*5)
                     = Squr(169 - 25)
                     = Squr(144)
                     = 12    

If top end is to be pulled down by 2 m then 

Length of ladder = 13 m
top Of ladder = 12 - 2 =10m
bottem of ladder = Squr(13*13 - 10*10)
                 = Squr(169 - 100)
                 = Squr(69)
                 = 8.3m

So bottom Of ladder is to be shifted by 8.3m - 5m = 3.3m 


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