Question

A 15 m long ladder reached a window 12 m
high from the ground on placing it against a
wall at a distance a. Find the distance of the
foot of the ladder from the wall.
12 cm
15 cm
а
(a) 10 m
(b) 9 m
(c) 8 m
(d) 4 m​

Answer 1

Answer:

(b) 9 m

Step-by-step explanation:

Given,

Length of ladder = 15 m

Length of wall from ground = 12 m

Now, Wall is perpendicular to Ground,

So, Together, Ladder, Wall and Ground from ladder to wall are forming a right angled triangle, right angle between wall and ground.

So, Hypotenuse of triangle = Length of ladder = 15 m

Perpendicular of triangle = Length of wall from ground = 12 m

Base of triangle = Distance from ladder's foot and wall's foot

Now, By Pythagoras theorem

(hypotenuse)^2 = (perpendicular)^2 + (base)^2

(15)^2 = (12)^2 + (Base)^2

225 = 144 + (base)^2

(Base)^2 = 225 - 144

(Base) = (81)^1/2

Base = 9 m

So, Distance from ladder's foot and wall's foot = Base = 9m