Question

An electrician has to repair an electric fault on a pole of height $5$m. She needs to reach a point $1.3$m below the top of the pole to undertake the repair work. What should be the length of the ladder that she should use which, when inclined at an angle of ${60}^0$ to the horizontal, would enable her to reach the required position? Also, how far the foot of the pole should she place the foot of the ladder? ( You may take $\sqrt{3}=1.73$).

• A. $\text{length of ladder}=7.4m$ , $\text{distance}=2.14m$
• B. $\text{length of ladder}=4.27m$ , $\text{distance}=3.7m$
• C. $\text{length of ladder}=4.27m$ , $\text{distance}=2.14m$
• D. $\text{length of ladder}=4.7m$ , $\text{distance}=2.14m$

Answer 1

The correct option is C $\text{length of ladder}=4.27m$ , $\text{distance}=2.14m$

$\sin 60°=\frac{3.7}{l}$

$\frac{\sqrt{3}}{2}=\frac{3.7}{l}$

$l=4.277m$

$\tan 60°=\frac{3.7}{x}$

$x=2.138$

$x\approx 2.14m$

Length of ladder $=4.27m$

Distance $=2.14m$