We could look at the midsegment TR as not part of the triangle and solve for the angles that way.
All the angles in a triangle= 180 degrees
We know that it is an isosceles triangle from the congruence marks, so two angles will have the same measure.
57+57+x= 180
114+x=180
x=66 The missing angle, or <SRU= 66
Since TR splits the triangle in half, and we know that the angles are congruent by the congruence marks, divide 66 by 2.
66/2= 33
m<TRU= 33 degrees
I hope this helps!
~kaikers
