7 ∠STM = 2 ∠S ∠S, ∠STR-?

∠R = 70°

∠STM = 2 ∠S

∠S + ∠R + ∠STM = 180°

∠S + 70° + 2∠S = 180°

3∠S = 110°

∠S = 110° ∶ 3 = 36,67°

∠STM = 2 × 36,67° = 73,34°

∠STR = 180° - ∠STM = 180° - 73,34° = 106,66°

Ответ: ∠S = 36,67°, ∠STR = 106,66°