A 15 m long ladder reached a window 12 m high form the ground on placing it against a wall at a distance a. Find the distance of the foot of the ladder from the wall.

It is given in the question that,

Length of ladder = 15 m

Height of ladder = 12 m

We have to find the distance of the foot of the ladder from the wall

Let the distance be a

According to Pythagoras theorem,

In a right angled triangle:

(Hypotenuse)^{2} = (Perpendicular)^{2} + (Base)^{2}

By applying Pythagoras theorem in the given question, we get:

(15)^{2} = (12)^{2} + (a)^{2}

225 = 144 + (a)^{2}

(a)^{2} = 225 - 144

(a)^{2} = 81

Hence,

a =

a = 9 m

10