Question

A ladder is standing on a horizontal ground and rests against a vertical wall. The ladder is 5.5m long and its foot is 3m from the wall. Calculate how far up tha wall the ladder will reach (Correct to 2 decimal places)

• A. 4.55m
• B. 4.61m
• C. 4.65m
• D. 4.5

Answer 1

The correct option is B 4.61m

In a $\Delta ABC$ right angled at B and C being the foot of the ladder
AC will correspond to the ladder, therefore $AC=5.5m$.
$BC=3m$
AB is what we need to find.
Applying pythagoras theorem in the $\Delta ABC$ we get
$A{B}^2+B{C}^2=A{C}^2$
$A{B}^2+3^2={5.5}^2$
$A{B}^2=30.25-9$
$AB=\sqrt{21.25}$
$AB=4.609$
$AB=4.61$ $\left(correctto2decimalplaces\right)$