00:00hello everyone welcome to Munirashwine Academy in this video we will be discussing angle sum
00:10property of polygons what do we understand by angle sum property so if we have a polygon
00:18suppose a triangle and we are talking about some of all the angles of the polygon means
00:26of triangle here in this case so if we have a triangle ABC angle sum will be sum of angle a
00:34plus angle B plus angle C now the sum of all the angles of a triangle is equal to 180 degree
00:43this is already done in last classes right so here we know that sum of angle a B and C will be 180
00:52degree now if we have another polygon suppose we have four sides we have five sides say four
00:57angles five angles six angles how will you find out the sum of these polygons right so there is a
01:04standard form which says sum of angles is equal to n minus 2 into 180 degree where n is the number of
01:14angles right so if I say I have a polygon with four sides a b c d so here we have four angles angle a
01:26angle B angle C and angle D what will be the sum of these four angles so it will be equal to n minus 2
01:35we have four here four angles so we can put it here and it will be say 4 minus 2 into 180 degree so 4
01:48minus 2 is 2 into 180 degree that is equals to 360 degree right 18 into 2 is 36 and 0 360 degree so sum of angles of a polygon with four angles is 360 degree
02:03now if I have a polygon with five angles okay so means a pentagon 1 2 3 4 5 here we have five angles 1 2 3 4 and 5 so n is equal to 5 here putting it in this formula we say n minus 2 into
02:32180 degree so n is equal to 180 degree so n is 5 minus 2 into 180 degree 5 minus 2 is 3 into 180 degree and 18 threes are is how much 3 8 the 24 3 1 the 3 and 4 5 5 5 40 degree so if we have five angles the sum or we say angle sum property or the sum of the angles of these five angles
03:02will be equal to 6 will be equal to 5 40 similarly if you have six angles in your polygon you will take n equal to 6 if you have seven angles you will take n equal to 7 and so on by putting in this standard formula you can find out the sum of all the angles of a given polygon I hope this is clear to you all
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