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   QUADRILATERALS  

LESSON 3

Few Instructions 

Welcome you all once again!

1. Note down  the work in your register on a regular basis..

2 AS ALREADY MENTIONED,YOU CAN USE ANY NOTEBOOK AVAILABLE AND SUBMIT SEPARATELY ONCE THE SCHOOL REOPENS.

3. Take your  Mathematics Register

4. Write chapters name  QUADRILATERALS and todays date 

Guidelines for the Blog

·         The text in BLUE, is to be written in your register

·         The text in Red is to be viewed by clicking on it

·         The text in Green is to be practiced for home work

·         Feel free to clarify your doubts by dropping a comment before going ahead in the lesson

       Yesterdays learning outcomes 

•        Evaluating unknown angle of a quadrilateral
•           Exterior angle property

Todays learning  outcomes  

I will be able to recall 
sum of all exterior angles is 360°
Evaluating each exterior angle of a regular polygon
An interior angle of regular polygon 

      What  is  exterior angle ?   click the link👇

                                                                         Exterior angle.

The Exterior Angle is the angle between any side of a shape, and a line extended from the next side.

      
      NOTE:- sum of exterior angle  and  its interior angle is 180 °
       Also known as linear pair angles .

     LETS  calculate exterior angle 'x'  in   EX 3.2 Q1 (b)  

         

 

SOLUTION 1 (b) (CW)

 By linear pairs of angles,

  ……….(i)

  ……….(ii)

  ……….(iii)

  ……….(iv)

   ……….(v)

Adding eq. (i), (ii), (iii), (iv) and (v),

 

 

         

     In these questions the  property used for evaluating 'x' is -------         ( yes ,it is linear pair  angles  )                   

NOTE  :  The sum of all exterior angles in a polygon is always 360 ° 

LETS SEE AN EXAMPLE 

WHAT DID U NOTICE IN THESE QUESTIONS  ? 

SUM  OF ALL EXTERIOR ANGLES IN EACH CASE  IS ....................

Homework 👆      

YESTERDAY WE STUDIED ABOUT REGULAR POLYGONS

SO HOW DO WE CALCULATE EXTERIOR ANGLE  OF A REGULAR POLYGON ? 

 IN A REGULAR  POLYGON  ( Do it in register)

Each exterior angle =  sum of exterior angles / n, 
where n= number of sides of polygon

Lets solve Q2(i)of Ex 3.2  using the above formula (CW)  

 click the given link, which  will help you to solve Q3(cw) and Q4 (Hw)

 To find interior and Exterior angle

HOMEWORK

 Ex 3.2 Q1 (a) , Q2 (ii) , 4,5 and 6

I would encourage the students to do the home work and then check the solutions 

Also practice the classwork

Thats all for today 

Have a good day