Question

A 5-m-long ladder whan set against the wall of a house reaches a height of 4.8 m. How far is the foot of the ladder from the wall?

Answer 1

Suppose the foot of the ladder is x m far from the wall.

Let the ladder is represented by AB, the height at which it reaches the wall be AC and the distance between the foot of ladder and wall be BC.

Then, by Pythagoras theorem:
$$\begin{gathered} A{B}^2=A{C}^2+B{C}^2 \\ \Rightarrow 5^2=4.8^2+x^2 \\ \Rightarrow x^2=25-23.04 \\ \Rightarrow x^2=1.96 \\ \Rightarrow x^2=(1.4{)}^2 \\ \Rightarrow x=1.4 \end{gathered}$$


Hence, the foot of the ladder is 1.4 m far from the wall.