Question

A ladder 5m long reaches a window 4m above the ground. the distance of the foot of the ladder from base of the wall will be

A. 2 m
B. 3m
C. 6m
D. None of the above​

Answer 1

B

Explanation:

This is modelled on a right triangle , 90° between the wall and the ground.

the legs are 4m and distance of ladder from the foot of the wall, x

the ladder is the hypotenuse of 5

using Pythagoras' identity in the right triangle

a² + b² = c²

a and b are the legs and c the hypotenuse , then

x² + 4² = 5²

x² + 16 = 25 ( subtract 16 from both sides )

x² = 9 ( take square root of both sides )

`√(x^2)` =
`√(9)`

x = 3

the foot of the ladder is 3m from the base of the wall