The angle of elevation of a ladder leaning against a house is 60° and the foot of the ladder is 6.5 m from the foot of the house. Find the length of the ladder in meters.
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → 13 meters
The ladder, the wall and the ground form a right-angled triangle with the ladder as the hypotenuse. The distance of the foot from the wall is the side next to the 60° angle, so cos 60° = base ÷ ladder.
\(\cos60^\circ=\displaystyle\frac{6.5}{L}\)
\(\displaystyle\frac{1}{2}=\frac{6.5}{L}\)
\(L=13\,\mathrm{m}\)