The foot of a ladder 25 m long is 7 m from the base of the building. If the top of the ladder slips by 4 m, then by how much distance will the foot of the ladder slide?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is option 4 i.e. 8 m
Formula used:
Pythagoras theorem,
Hypotenuse2 = base2 + perpendicular2
Calculations:
AB is the height of the building, BC is the base distance and AC is the length of ladder.
Using equation (1), we get
⇒ 252 = AB2 + 72
⇒ 625 = AB2 + 49
⇒ 576 = AB2
⇒ AB = 24 m
When the ladder is slided from the top of the building, the building becomes 24 - 4 = 20 cm
Applying equation (1) in triangle DBE, we get
⇒ DE2 = DB2 + BE2
⇒ 252 = 202 + BE2
⇒ BE2 = 625 - 400 = 225
⇒ BE = 15 m
Distance Slided by the ladder = CE = 15 - 7 = 8 m