Cho hình vẽ . Tính \(x\)?
Xét tam giác \(ACF\) có \(\widehat{A}+\widehat{ACF}+\widehat{AFC}=180^0\) \(\Rightarrow\) \(\widehat{ACF}=180^0-\widehat{A}-\widehat{AFC}=180^0-60^0-90^0=30^0\)
Xét tam giác \(IEC\) có \(\widehat{IEC}+\widehat{ICE}+\widehat{EIC}=180^0\) \(\Rightarrow\) \(90^0+30^0+x=180^0\) \(\Rightarrow x=60^0\)
