The
correct answer is in file attached
we have
triangle RST
m∠R = 60, m∠S = 80 and m∠T=180-(80+60)=40
RS=4
triangle EFD
m∠F = 60, m∠D = 40 and m∠E=180-(60+40)=80
EF=4
Therefore
The triangles RST and EFD are
congruents because they have two angles and the side common to them,
respectively, equal.
This is the theorem of ASA (angle-side-angle).
Explication
Side common--------> RS=EF
Angles RS------------- > m∠R =
60 m∠S =
80
Angles EF------------- > m∠E =
80 m∠F = 60
Angles RS and Angles EF are equals
The segment which is congruent
to RT is FD, because angles of RT are 60 and 40, and angles of FD also are 60
and 40.
