1) To better visualize it let's draw that bisected angle
According to the Bisector theorem, those angles are congruent therefore we can write an equation:
3x-2=9x-26
-2+26=9x-3x
24=6x
6x=24
x=4
m RST = (3x -2) + (9x -26)
m RST = 3(4) -2 +9(4) -26
m RST = 12 -2 +36 -26
m RST = 10 +10
mRST = 20º
