Question

Choose the correct answer from the alternative given.
A $10$ m long ladder is placed against a wall. It is inclined at an angle of $30$ to the ground. The distance (in m) of the foot of the ladder from the wall is?

Given $(\sqrt{3}$ = 1.732)

• A. $7.32$
• B. $8.26$
• C. $8.66$
• D. $8.16$

Answer 1

The correct option is C $8.66$

AC $=10m$
BC =:?
$\angle$ACB = $\theta$ =${30}^{\circ }$
From $\Delta$ABC,
$\cos$ $\theta$ = $\frac{BC}{AC}$

$\cos$ ${30}^{\circ }$ =$\frac{BC}{10}\Rightarrow \frac{\sqrt{3}}{2}=\frac{BC}{10}$

$BC=5$$\sqrt{3}$ $=5$ $\times$ $1.732=8.660$ metre