117 °
Explanation
when a line intersects a pair of parallel lines, vertical angles, corresponding angles interior alternate angles and exterior alternate angles are formed
then
[tex]\begin{gathered} m\measuredangle5\text{ is congruent with m}\measuredangle1 \\ so \\ m\measuredangle5\text{ = m}\measuredangle1 \end{gathered}[/tex]
and
[tex]\begin{gathered} m\measuredangle1+m\measuredangle3=\text{ 180} \\ \text{if m}\measuredangle5=63 \\ 63=m\measuredangle1,replace \\ 63+m\measuredangle3=180 \\ \text{subtract 63 in both sides} \\ 63+m\measuredangle3-63=180-63 \\ m\measuredangle3=117 \end{gathered}[/tex]
I hope this helps you
