The sum of the internal angles of a triangle is 180°. Therefore:
[tex]m\angle E+m\angle F+m\angle G=180[/tex]
Solving for m∠F:
[tex]\begin{gathered} 47+m\angle F+86=180 \\ 133+m\angle F=180 \end{gathered}[/tex]
Subtract 133 on both sides:
[tex]\begin{gathered} 133+m\angle F-133=180-133 \\ m\angle F=47 \end{gathered}[/tex]
Answer: C. 47°
