Question

I need help please ....

Answer 1

It's hard to read your image, unfortunately.  Seems to me that it states that C=50.2 and that the formula for circumference is C=2pi*r.
   
                                                                    50.2
In that case, C= 50.2 = 2(3.14)r, and  r = ------------- = 7.99.  
                                                                    6.28

We are to round this to one decimal place.  That results in r = 8.0.