a+b+c+d =360grade
a/1/2 =b /1/4 =c /1/6 =d/1/12
a/1/2 =b/1/4 +c /1/6 =d /1/12 =a+b+c+d /1/2+1/4+1/6+1/12 =
=360 /6+3+2+1 /12 =360*12/12 = = 360 grade
a/1/2 =360 ; a =360/2 =180 gr
b /1/4 =360 ;b =360/4 =90 gr
c /1/6 =360 ; c=360/6 =60 gr
d /1/12 =360 ; c =360/12 =30 gr
( V : 180+90+60+30 =360 grade )
