[tex]here \\ \angle 6 = 75 \degree \\ we \: know \: that \\ \angle6 + \angle 8 = 180 \degree \\ \implies 75 \degree \: + \angle 8 = 180 \degree \\ \implies \angle8 = 180 \degree - 75 \degree \\ \implies \angle8 = 105 \degree \\ since \: line \: l \parallel \: line \: m \\ \angle 8 = \angle3 \: (corresponding \: angles) \\ therefore \: \angle3 = 105 \degree[/tex]
