# The angle of elevation of a ladder leaning against a wall is 60º and the foot of the ladder is 4.6 m away from the wall. The length of the ladder is:

A. 2.3 m B. 4.6 m C. 7.8 m D. 9.2 m Answer: Option D
$\begin{array}{l}\text{Let AB be the wall and BC be the ladder.}\\ \angle\mathrm{ACB}=60^{\circ}\text{ and }\mathrm{AC}=4.6\mathrm{~m}\\ \frac{\mathrm{AC}}{\mathrm{BC}}=\cos 60^{\circ}=\frac{1}{2} \\ \Rightarrow \mathrm{BC}=2 \times \mathrm{AC} \\ =(2 \times 4.6) \mathrm{m} \\ =9.2 \mathrm{~m} \end{array}$