New question related to schwarzschild radius

Sun massed black-hole?

* Q.1. Calculate the radius of a black hole that has the same Mass of Sun.

Ans:            this is our Formula
$$m =\text{ Mass of the sun} = 1.989x10^30 kg$$

  

$$G =\text{ gravitational constant} = 6.672x10^-11 Nm^2/kg^2$$

$$c = 2.9979x10^8 m/s$$
so:
         
$$R  =2 * 6.672x10^-11 * 1.989x10^30/(2.9979x10^8)^2$$

$$R  = (  2.65412x10^20  ) / (  8.98740441x10^16  )$$

$$R  = 2953.156973 m   or   2.953 km$$
              

                                 

* I am currently reading this book  "voyages through the universe ,third edition by Frankoi ,Morrison ,Wolff ",this book has some exercise which have no answers ,here I am solving the question on my own for knowledge .