Line of sight
The line of sight is the straight line joining the observer's eye to the object being seen.
Practice This ConceptMain explanation
Teacher explanation
In trigonometry problems, the line of sight is the slant line that connects the observer and the target object. It is the key line used to form the angle of elevation or depression. Without this line, we cannot build the right triangle needed for height and distance questions. The line of sight is always straight, not curved, because we imagine the shortest viewing path.
Example
If a student at ground level sees the top of a lamp post, the straight line from the eye to the lamp post top is the line of sight.
Simple analogy
Sight line means the straight line your eyes follow to the object.
Common confusion
Students sometimes confuse the line of sight with the ground distance or with a ladder leaning against a wall.
Exam tip
Mark the line of sight first in every sketch. It helps you find the angle and the right triangle quickly.
Answer writing and exam use
1-mark use
Write the exact meaning of line of sight in one clean line.
2-mark use
Define line of sight and add one example or condition.
3-mark use
Explain line of sight, show the method or example, and mention the common mistake.
Practice this concept with focused MCQs
Open the concept quiz intro first, review the test details, and then start a focused MCQ set from this concept only. Instant score and answer review are live now.
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