we know that
in the right triangle RST
sin 60°=RS/RT-------> RT=RS/sin 60°----> RT=2√3/(√3/2)---> 4
RT=4 units
in the right triangle QRT
RQ=RT-------> by angle 45°
tan 45=RQ/RT-----> RQ=RT*tan 45°
tan 45°=1
so
RQ=RT*1------> RQ=4
hence
x=4
the answer is
x=4 units