Solve the 4

Here u go my friend :-

Let r be the radius of the circle and θ the number of radians in the angle.
Then rθ+2r=πr or θ=(π−2) radians
or θ=(π−2)×π180​
or =180−2×5717′44.8′′ 
or θ=180−11435′29.6′′=6524′30.4′′