a=20gr
b=40gr
a+b+c=180gradusov(gr)
60+c=180
c=120
a/sina=c/sinc
a/20=12/120
a=240/120=2
R=a/2sina
R=2/2sin20
R=1/sin20 pods4itaem na kal'kulyatore => sin20 priblizitel'no 0,34
R=1/0,34= 2,9
a=20gr
b=40gr
a+b+c=180gradusov(gr)
60+c=180
c=120
a/sina=c/sinc
a/20=12/120
a=240/120=2
R=a/2sina
R=2/2sin20
R=1/sin20 pods4itaem na kal'kulyatore => sin20 priblizitel'no 0,34
R=1/0,34= 2,9