(1) x=m<RQT=[m arc(RST)]/2
m arc(RST) + m arc(RQT)=360° (2)
m<RST=130°=[m arc(RQT)]/2
Solving for m arc(RQT):
2*130°=2*[m arc(RQT)]/2
260°=m arc(RQT)
m arc(RQT)=260°
Replacing m arc(RQT) by 260° in equation (2):
(2) m arc(RST) + m arc(RQT)=360°
m arc(RST) + 260°=360°
Solving for m arc(RST):
m arc(RST) + 260°-260°=360°-260°
m arc(RST) =100°
Replacing m arc(RST) by 100° in equation (1):
(1) x=m<RQT=[m arc(RST)]/2=100°/2→x=50°
Answer: Fourth option 50