Question

a ledder reaches WINDOW WHICH IS 12m above the ground on one side of the street , keeping its foot at the same point , the lader is turned to other side of the street to reach a window 9m high .find the width of the street if the length is 15m......... urgent ...... :)

Answer 1

refer to diagram
CA = 12 m
DB = 9 m
AB = ?
ladder ht. same in both case = 15 m
in Δ APC by Pythagoras theorem
 CA² + AP² = CP² ⇒ CA² = 225 - 144 = 81 ⇒ CA = 9 m
similarly in ΔBPD
DB² + BP² = DP² ⇒  BP² = 225-81 = 144 ⇒ BP = 12m
width of street AB = AP+BP = 12+9= 21m
that's it 

Answer 2

Answer:

Step-by-step explanation:

ladder ht. same in both case = 15 m

in Δ APC by Pythagoras theorem

 CA² + AP² = CP² ⇒ CA² = 225 - 144 = 81 ⇒ CA = 9 m

similarly in ΔBPD

DB² + BP² = DP² ⇒  BP² = 225-81 = 144 ⇒ BP = 12m

width of street AB = AP+BP = 12+9= 21m