AB=b=3, BC=a=2, AC=c
sin80=0,9848
по т. синусов:
АВ/sinC = BC/sinA = AC/sinB
3/0,9848 = 2/sinA
3*sinA = 2*0,9848
3*sinA = 1,9696
sinA = 0,6565333...
sinA=0,6565
уголА=41° 2'
угол B примерно= 180-(41°2'+80)=180 -(121° 1’ 60”)
угол B= 58°58'
sin58° 58' =0.8569
BC/sinA = AC/sinB
2/0,6565 = AC/0,8569
AC*0,6565 = 2*0,8569
AC*0,6565 = 1,7138
AC=2,61105....
AC примерно = 2,6
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по т. косинусов
с² = a² + b² - 2*a*b*cosC
c² = 2² + 3² - 2*2*3*cos80
cos80 = 0,1736
c² = 4 + 9 - 12*0,1736
c² = 13 - 2,0832
c² = 10,9168
c = √(10,9168)
c примерно = 3,3