Răspuns:
Explicație pas cu pas:
arc AD=360°-(110°+70°+130°=360°-310°=50°
a)∡DAB=(arcCD+arc BC)/2=(130°+70°)/2=200°/2=100°
∡ABC=(arcCD+arc AD)/2=(130°+50°)/2=90°
∡BCD=(arcAD+arcAB)/2=(50°+110°)/2=80°
∡CAD=(arc AB+arc BC)/2=(110°+70°)/2=90°
b)∡AOB=arc AB=110°
∡BOC=arc BC=70°
∡COD=arc CD=130°
∡DOA=arc DA=50°