A 20 m long ladder is placed against a wall such that it reaches a height of 10 m. What is the angle the ladder makes with the ground?
Answer: A
The ladder is the hypotenuse (20 m) and the height on the wall is the opposite side (10 m).
Let θ be the angle with the ground.
\(\sin \theta = \frac{\text{Opposite}}{\text{Hypotenuse}} = \frac{10}{20} = \frac{1}{2}\).
The angle whose sine is 1/2 is 30°.