a) Ta có: \(a//Gx\)\(\Rightarrow\widehat{aEG}=\widehat{G_1}\) (hai góc so le trong)
\(\Rightarrow\widehat{G_1}=42^o\) (vì \(\widehat{aEG}=42^o\))
b) Có: \(\widehat{GFy}+\widehat{GFb}=180^o\) (hai góc kề bù)
\(\Rightarrow138^o+\widehat{GFb}=180^o\) (vì \(\widehat{GFy}=138^o\))
\(\Rightarrow\widehat{GFb}=180^o-138^o=42^o\)
c) Ta thấy: \(Gx//b\)\(\Leftrightarrow\widehat{G_2}=\widehat{GFb}=42^o\) (hai góc so le trong)
Lại có: \(\widehat{EGF}=\widehat{G_1}+\widehat{G_2}\) (hai góc kề nhau)
\(\Rightarrow\widehat{EGF}=42^o+42^o=84^o\left(cmt\right)\)
#Urushi
a) Do Gx // a
⇒ ∠G₁ = ∠GEa = 42⁰ (so le trong)
b) Ta có:
∠GFb + ∠GFy = 180⁰ (kề bù)
⇒ ∠GFb = 180⁰ - ∠GFy
= 180⁰ - 138⁰
= 42⁰
c) Do Gx // b
⇒ ∠G₂ = ∠GFb = 42⁰ (so le trong)
⇒ ∠EGF = ∠G₁ + ∠G₂
= 42⁰ + 42⁰
= 84⁰
a) \(\widehat{G_1}\) = 42o
b) \(\widehat{GFb}\) = 42o
c) \(\widehat{EGF}\) = 84o