Finding radius of curvature and focal length of mirrors

[rhxoehwhfh]

A concave mirror has a focal length of 26 cm. What is the radius of curvature of the mirror?

and also

The radius of curvature of a convex mirror is 60 cm. What is the focal length of the mirro?

Can anyone tell me the formula for finding each of the answer?...

 

[Shooting Star]

R has always the absolute value of 2f.

 

[rhxoehwhfh]

what is R and what is 2f , can you specify it for me please..

 

[Shooting Star]

R is the radius of curvature anf f is the focal length.

 

[rhxoehwhfh]

so formula for this is R=2f?

 

[Shooting Star]

Yes.