Trigonometry

Concept: The angle of depression is equal to the angle of elevation. Using right triangle trigonometry:
Step 1: Interpret the problem. Height of cliff = 100 m Angle of depression = So angle of elevation from the boat = . Let distance from foot of cliff = m.
Step 2: Apply tangent ratio.
Step 3: Solve for .
Conclusion: The distance of the boat from the foot of the cliff is 100 m.