M list the sides of ABC in order from shortest to longest
Sum of angles in a triangle = 180
Angles A + B + C = 180
80 + 3x + 5 + 5x - 1 = 180
3x + 5x = 180 - 80 - 5+1
8x = 96
x = 96/8
x = 12
So angle A = 80, B = 3x + 5 = 3*12 + 5 = 36 + 5 = 41, C = 5x - 1 = 5*12 - 1 = 60 - 1= 59
Angle A = 80, B = 41, C = 59
So the smallest side is the side facing the smallest angle and the largest side is the side facing the largest angle.
So from the smallest to biggest side:
AC < AB < BC
Arigatou gozaimasu!!