NAMING OF ANGLES AND ITS INTERIOR N EXTERIOR REGION (ex 4.3) 19-5-20

GOOD MORNING BOYS ! Welcome to another class of math. 

LEARNING OUTCOMES OF THIS CLASS-
By the end of this class you will be able to-
-name angles
- name points in the interior of an angle
-name points exteriror of an angle
-name points that are common to two angles

An angle is formed where two rays  meet.
-The two rays forming the angle are called the arms of the angle.
-The common end point where the rays meet is called vertex.






INTERIOR AND EXTERIOR OF AN ANGLE-
Interior of an angle is the area that lies between the arms of an angle.
Exterior of an angle is the area outside the arms of an angle.




So, in the above angle , point D is interior of the angle . Point E  is exterior of the angle.

Points can also be ON the arms of an angle, as shown in the figure below-





EXAMPLE-




TRY THIS !

In the angle QOP given above name-
a) the points interior of the angle
b) the points exterior of the angle

Now you can do questions 2 of exercise 4.3 ,on page 80 of your reader.

In the figure given below angles 1 and 2 have a common arm.



EXAMPLES OF DRAWING TWO ANGLES WITH COMMON POINTS




Now you can do question 3 of exercise 4.3 on page 80 of your reader.

The first question  of ex.4.3 is done below

Question 1.Name the angles in the given figure. ( refer to your reader for the figure)

Answer: There are four angles in given figure:

$\mathrm{\angle }$ABC, 
$\mathrm{\angle }$CDA, 
$\mathrm{\angle }$DAB, 
$\mathrm{\angle }$DCB