we know that
m∠PTS=m∠RTQ -----> by vertical angles
Step 1
m∠RTQ+m∠QTS=[tex]180\°[/tex] -------> by supplementary angles
solve for m∠QTS
m∠QTS=[tex]180\°[/tex]-m∠RTQ -------> equation [tex]1[/tex]
Step 2
m∠PTS+m∠QTS=[tex]180\°[/tex] -------> by supplementary angles
solve for m∠QTS
m∠QTS=[tex]180\°[/tex]-m∠PTS -------> equation [tex]2[/tex]
Step 3
equate equation [tex]1[/tex] and equation [tex]2[/tex]
[tex]180\°[/tex]-m∠RTQ=[tex]180\°[/tex]-m∠PTS
-m∠RTQ=-m∠PTS
so
m∠RTQ=m∠PTS
therefore
the answer is the option A
Sum of the measures of angles RTQ and QTS is 180°