A ladder of length 10 m leans against a vertical wall. If the ladder makes an angle of 60° with the horizontal ground, how high up the wall does the ladder reach?

The height reached on the wall is the side opposite the 60° angle, so height = 10 × sin 60° = 10 × (√3/2) = 5√3 m. Option B (5 m) results from using sin 30° instead, and option C comes from multiplying 10 by √3 without dividing by 2.