Răspuns:
Explicație pas cu pas:
a)
∡DOE= 90*2/3=60°
90-x+x+x+60=180°
2x-x= 180-90-60
x=180-150
x=30°
-
∡BOC= 30°
-
-
b)
∡EOA= 90-30=60°
∡DOE=60°
∡AOD= ∡DOE+∡EOA
∡AOD= 60+60=120→OE= bisectoarea ∡AOD
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c)
∡AOE=60°
OF= bisectoarea ∡AOE→FOA=30°
∡AOC=30°
∡COB=30°
∡FOB= 30+30+30
∡FOB=90°
∡BOD= unghi alungit = 180°
∡FOB=90°
∡FOD=180-90
∡FOD= 90°
∡FOD=∡FOB=90°
↓
OF= bisectoarea ∡ BOD
