• # question_answer A ladder, leaning against a wall/makes an angle of $60{}^\circ$ with the horizontal. If the foot of the ladder is 2.5 m away from the wall, find the length of the ladder.

 Let AB be the ladder leaning against a wall AC. Then,                            $\cos \,60{}^\circ =\frac{BC}{AB}$ $\frac{1}{2}=\frac{2.5}{AB}$ $AB=2.5\times 2=5\,m$ $\therefore$ Length of ladder is $5\text{ }m$.