Question

Hey could you help me out with this question I have been stuck in this question

Answer 1

`\begin{gathered} \text{triangle sum theorem says:} \\ \angle1+\angle2+\angle3=180 \end{gathered}`

`\begin{gathered} \text{can you se}e\text{ my message ?} \\ \text{its uploading} \end{gathered}`
`\begin{gathered} \text{substraction property of equality} \\ \angle1+\angle2=\angle m4 \end{gathered}`