Line of Sight
When an observer looks from a point E (eye) at an object O then the straight line EO between the eye E and the object O is called the line of sight.
Horizontal
When an observer looks from a point E (eye) to another point Q which is horizontal to E, then the straight line, EQ between E and Q is called the horizontal line.
Angle of Elevation
When the eye is below the object, then the observer has to look up from the point E to the object O. The measure of this rotation (angle θ) from the horizontal line is called the angle of elevation.
Angle of Depression
When the eye is above the object, then the observer has to look down from the point E to the object. The horizontal line is now parallel to the ground. The measure of this rotation (angle θ) from the horizontal line is called the angle of depression.
NCERT Solutions Ch- 9 Maths
