Done By:Name: Gourisankaran PillaiClass: 10 ESchool: Christ Nagar Central School

Trigonometry is a branch of mathematics

that studies triangles and the relationships

between their sides and the angles between

these sides.

In this topic we shall make use of Trigonometric Ratios to

find the height of a tree, a tower, a water tank, width of a river, distance of ship from

lighthouse etc.

Line of Sight

Horizontal

The angle which the line of

sight makes with a

horizontal line drawn away

from their eyes is called the

angle of Elevation of

aeroplane from them.

Angel of Elevation

If the pilot of the aeroplane looks downwards at any object on the ground then the Angle between his line of sight and horizontal line drawn away

from his eyes is called ‘Angle of Depression.’

Angle of Depression

Horizontal

Angle of

Depression

Now let us Solve some problem related to

Height and Distance

Sol:- Let AB be the tower and the angle of elevation from point C (on ground) is 30°.

In ΔABC,

.

Therefore, the height of the tower is .

Sol:- It can be observed from the figure that AB is the pole.In ΔABC,

Therefore, the height of the pole is 10 m.

Sol:- Let K be the kite and the string is tied to point P on the ground.In ΔKLP,

.

Hence, the length of the string is .