Răspuns:
Explicație pas cu pas:
a)
<BOC = 5/4*<AOB
<COD = 6/4*<AOB
<AOD = 9/4*<AOB
<AOB + <BOC + <COD + <AOD = 360°
<AOB + 5/4*<AOB + 6/4*<AOB + 9/4*<AOB = 360°
24/4*<AOB = 360°
6*<AOB = 360°
<AOB = 360° : 6 = 60°
<BOC = 5*60°/4 = 75°
<COD = 6*60°/4 = 90°
<AOD = 9*60/4 = 135°
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b) <AOD/2 + <AOB + <BOC/2 = 135°/2 + 60° + 75°/2 = 210°/2 + 60° = 105° + 60° = 165°