O is the circle,Is this correct or not if not modify it

Hello Irfan,
Your figure is not clear to me as there is no sign of 'M'.
By the way, Here is the simplest solution to this question.
Here,

OT = OS = r and OP = 2r (Given)

In ∆TOP

➭ Sin ∠TPO = TO/OP

➭ r/2r

➭ 1/2

Since, Sin 30° = 1/2

∴ ∠TPO = 30°

Similarly, ∠OPS = 30°

Now,

➭ ∠TPS = ∠TPO + ∠OPS

➭ 30° + 30°

➭ 60°

As we know that :- ∠TPS + ∠TOS

= 180°

So,

➭ ∠TOS = 180° - ∠TPS

➭ 180° - 60°

➭ 120°

Now, In ∆TOS, Let

➭ ∠OST = ∠OTS = x°

Also,

➭ ∠TOS + x° + x° = 180°

➭ 120° + 2x° = 180°

➭ 2x° = 60°

∴ x° = 30°

Hence, ∠OST = ∠OTS = 30°.