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dm thằng súc vật nguyễn đức anh
╚{AV♀N░≡┤E╞
(Mình vẽ hơi xấu, mong bạn thông cảm)
Ta có \(\widehat{O}_1+\widehat{O_2}=180^o\)(kề bù)
và \(\widehat{O_1}+\widehat{O_2}+\widehat{O_3}=240^o\)(gt)
=> \(180^o+\widehat{O_3}=240^o\)
=> \(\widehat{O_3}=60^o\)
=> \(\widehat{O_3}=\widehat{O_1}=60^o\)(đối đỉnh)
Ta lại có \(\widehat{O}_2=180^o-\widehat{O_3}\)(kề bù)
và \(\widehat{O_2}=\widehat{O_4}\)(đối đỉnh)
=> \(\widehat{O_2}=\widehat{O_4}=180^o-\widehat{O_3}\)
=> \(\widehat{O_2}=\widehat{O_4}=180^o-60^o=120^o\)