A ladder leans against a vertical wall, making an angle of 60° with the ground. If the foot of the ladder is 5m away from the wall, what is the length of the ladder?
Correct: B
Let the length of the ladder be 'L'. The distance from the wall to the foot of the ladder is 5m, which is the Adjacent side to the angle of 60°. The length of the ladder is the Hypotenuse. We use the cosine function: cos(angle) = Adjacent / Hypotenuse. cos 60° = 5 / L. We know cos 60° = 1/2. So, 1/2 = 5 / L. Cross-multiplying gives L = 2 × 5 = 10 m.