Page 1 - Lesson Notes
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SAI International School


                                               Class :  VI


           Mathematics

           Chapter - 5 – Understanding Elementary Shapes


           Lesson Note -3

           Subtopics:


                       Measuring angles using protractor
                         Perpendicular lines




                 The protractor:

                        We have a special instrument for measuring angles. It is called a protractor. Look
                         at the picture of a typical protractor with its important parts labelled.

























                 Measuring angle by a protractor:
                                Place your protractor on top of the angle. Make sure the origin is exactly on
                  the vertex of the angle, and the base line is exactly on top of one of the arms of the
                  angle. Keep adjusting the position of the protractor until the origin and the base line are
                  exactly lined up.
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