Answer:
-2/3= -20/30
2/3 = 20/30
so rational numbers in between are
-19/30, -18/30, -17/30,........ -1/30, 0,+1/30,.............+17/30, +18/30, +19/30
so you can write as many as you like
sum of interior angle of a triangle is 180 degree
so,
3x +7 + 2x+7 +3x+6 = 180
8x + 20 = 180
8x = 180 - 20
8x = 160
x = 160/ 8
x = 20
May it will help you