Answer:
The Part 4 can be written as;
[tex]\begin{gathered} m\angle A+m\angle B=180^{\circ} \\ m\angle A+m\angle D=180^{\circ} \end{gathered}[/tex]
Explanation:
From part 3;
[tex]\begin{gathered} 2m\angle A+2m\angle B=360^{\circ} \\ 2m\angle A+2m\angle D=360^{\circ} \end{gathered}[/tex]
Applying the Division property of equality;
[tex]\begin{gathered} \text{If;} \\ a+b=c \\ \text{then;} \\ \frac{a}{n}+\frac{b}{n}=\frac{c}{n} \end{gathered}[/tex]
Divide the equations through by 2;
[tex]\begin{gathered} 2m\angle A+2m\angle B=360^{\circ} \\ \frac{2m\angle A}{2}+\frac{2m\angle B}{2}=\frac{360^{\circ}}{2} \\ m\angle A+m\angle B=180^{\circ} \end{gathered}[/tex][tex]\begin{gathered} 2m\angle A+2m\angle D=360^{\circ} \\ \frac{2m\angle A}{2}+\frac{2m\angle D}{2}=\frac{360^{\circ}}{2} \\ m\angle A+m\angle D=180^{\circ} \end{gathered}[/tex]
Therefore;
The Part 4 can be written as;
[tex]\begin{gathered} m\angle A+m\angle B=180^{\circ} \\ m\angle A+m\angle D=180^{\circ} \end{gathered}[/tex]
