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?

8 m

⇒ Using pythagoras theorem in 1st figure i.e; triangle ABC, we get

⇒ AB = 24 m

Now,

Applying Pythagoras theorem in triangle DBE

⇒ \( {DE }^{ 2} \) = \( {DB }^{2 } \) + \( {BE }^{2 } \)

⇒ \( {25 }^{ 2} \) = \( {20 }^{2 } \) + \( {BE }^{2 } \)

⇒ 625 - 400 = \( {BE }^{2 } \)

⇒ \( {BE }^{2 } \) = 225

⇒ BE = 15m

⇒ CE = 15 - 7 = 8m.

Therefore, foot of the ladder slide by 8m.