Answer:
126
Step-by-step explanation:
∠S : ∠T = 7:3
∠S = 7x
∠T = 3x
∠S + ∠T = 180 {Supplementary angles}
7x + 3x = 180
10x = 180
Divide both sides by 10
x = 180/10
x = 18
∠S = 7x = 7*18 = 126°
