a) Vì \(a//b\) nên \(\widehat{B_{1}}=\widehat{A_{4}}=37^{\circ}\) (hai góc so le trong)
b) Ta có: \(\widehat{A_{1}}\) và \(\widehat{A_{4}}\) kề bù
nên \(\widehat{A_{1}}+\widehat{A_{4}}=180^{\circ}\)
\(\Rightarrow \widehat{A_{1}}=180^{\circ}-\widehat{A_{4}}\)
\(=180^{\circ}-37^{\circ}=143^{\circ}\)
\(a//b\) nên \(\widehat{A_{1}}=\widehat{B_{4}}=143^{\circ}\) (hai góc đồng vị).
c) Cách 1: \(\widehat{B_{2}}=\widehat{B_{4}}=143^{\circ}\) (hai góc đối đỉnh);
Cách 2: \(\widehat{A_{1}}=\widehat{B_{2}}=143^{\circ}\) (hai góc so le trong);
Cách 3: \(\widehat{B_{2}}+\widehat{A_{4}}=180^{\circ}\) (hai góc trong cùng phía bù nhau)
nên \(\widehat{B_{2}}=180^{\circ}-\widehat{A_{4}}=180^{\circ}-37^{\circ}=143^{\circ}\)
