Trigonometry is the study of the properties of triangles.
"Tri" is Ancient Greek word for three,
"gon" means side,
"metry" measurement
Together they make "measuring three sides". If you know some facts about a triangle, such as the lengths of its
sides, then using trigonometry you can find out other facts about it. If
you know the lengths of sides then you can find what the angles are. If
you know the length of one side and of two of the angles, then you can
work out what the remaining angle is, and also what the lengths of the
other two sides are. As a consequence the Ancient Greeks were able to use trigonometry to calculate the distance from the Earth to the Moon.
DEFINITION:
The branch of mathematics that deals with
the relationships between the sides and the angles of triangles and the
calculations based on them, particularly the trigonometric functions.
APPLICATIONS IN REAL LIFE
Trigonometry is commonly used in finding the height of towers and mountains.
It is used in navigation to find the distance of the shore from a point in the sea.
It is used in oceanography in calculating the height of tides in oceans
It is used in finding the distance between celestial bodies
The
sine and cosine functions are fundamental to the theory of periodic
functions such as those that describe sound and light waves.
Architects
use trigonometry to calculate structural load, roof slopes, ground
surfaces and many other aspects, including sun shading and light angles
LINE OF SIGHT
An imaginary line from the eye to a perceived object.
An unobstructed path between sending and receiving antennas
Angles of Elevation and Depression
When a person looks at something above
his or her location, the angle between the line of sight and the horizontal is
called the angle of elevation. In this case, the
line of sightis “elevated” above the horizontal.When a person looks at something below his or
her location, the angle between the line of sight and the horizontal is called
the angle of depression. In this case, the
line of sight is “depressed” below the horizontal. Since the vertical and horizontal
directions are perpendicular, the elements of problems dealing with the
relationship between lines of sight and the horizontal lead naturally to right
triangles:
Angles of elevation and
depression are formed by the horizontal lines that a person’s lines of sight to
an object form. If a person is looking up, the angle is an elevation angle. If
a person is looking down, the angle is a depression angle.
