Answer:
see explanation
Step-by-step explanation:
The sum of the 3 angles in the triangle = 180°
Sum the 3 angles and equate to 180
31 + x + 4 + 3x + 9 = 180, that is
4x + 44 = 180 ( subtract 44 from both sides )
4x = 136 ( divide both sides by 4 )
x = 34
Thus
∠ S = x + 4 = 34 + 4 = 38°
∠ T = 3x + 9 = 3(34) + 9 = 102 + 9 = 111°
