Question

Answer 1

\(\widehat{A_1}=110^o\) thì a//b nha

a) Ta có:

\(\widehat{A_1}+\widehat{B_1}=110^o+70^o=180^o\)

mà 2 góc có vị trí trong cùng phía

=> \(a\)//\(b\)

b) \(\widehat{C_2}=180^o-50^o=130^o\)

\(\widehat{D_3}=\widehat{D_1}\left(\text{đối đỉnh}\right)\) mà \(\widehat{D_3}=\widehat{C_1}=50^o\left(\text{đồng vị}\right)\)

\(\Rightarrow\widehat{D_3}=\widehat{D_1}=50^o\)

\(\widehat{D_2}=\widehat{D_4}\left(\text{đối đỉnh}\right)\) mà \(\widehat{D_2}=\widehat{C_2}=130^o\left(\text{đồng vị}\right)\)

Vậy ...