The angle of elevation of a ladder leaning against a wall is 60° and the foot of the ladder is 4.6 m away from the wall. What is the length of the ladder?
Answer: D
Let the length of the ladder be L (the hypotenuse) and the distance from the wall be D (the adjacent side).
We use the cosine function: \(\cos \theta = \frac{\text{Adjacent}}{\text{Hypotenuse}}\).
\(\cos 60° = \frac{4.6}{L}\)
We know \(\cos 60° = 1/2\).
\(\frac{1}{2} = \frac{4.6}{L}\)
L = 4.6 × 2 = 9.2 meters.