Răspuns:
arcAB=100°. arcBC=120°, arcDC=80° ,
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<A=?: <B=?; <C=?; <D=?
arcAB+arcBC+arc CD=100+120+80=300°=>
arcDA=360-300=60°
<A=arcBD/2=(arcBC+arcCD)/2=(120+80)/2=200/2=100°
<B=arc(CA)/2=(arcCD+arcDA)/2=(80+60)/2=140/2=70°
<C=arcDB/2=(arcDA+arc AB)/2=(60+100)/2=80°
<D=arcAC/2=(arcAB+arcBC)/2=(100+120)/2=110°
Explicație pas cu pas:
