BHARATIYA VIDYA BHAVAN’S
SMT. M. K. PATEL SCHOOL, NARSANDA
SUBJECT: MATHEMATICS
CLASS: VIII
ACTIVITY
CHAPTER 3
UNDERSTANDING QUADRILATERAL
Aim: To verify the property of external
angles of a polygon.
“Sum of external angles of a
polygon is 360.”
STEP 1:Draw a circle of any radius.
STEP 2: Put pointer of the compass on
the circle and draw an arc with the radius
same as of circle, which intersect the
circle.
 Take intersection of circle and arc as centre
and draw another arc on the circle.
 Continue the process of drawing arcs, to get 6
such arcs on the circle.
STEP 3: Join the points of intersection
of arcs and circle to get a Hexagon.
STEP 4: Draw external angles by extending the
sides of the Hexagon in the exterior.
STEP 5: Take a small radius and intersect
the exterior angle by drawing an arc. (Do
it for all angles)
STEP 6: Shade all angles with different
colours as shown in the figure.
STEP 7: Cut out all the external angles
along the lines of angles as shown.
Step 8: Arrange all the 6 angles as shown.
OBSERVATION
 We observe that all the angles together
forms a complete circle.
CONCLUSION
 We conclude that sum of measures of all the
exterior angles of any polygon is always 360
degree.
Thank You