Answer
$R=-20cm$
Work Step by Step
To find the radius of curvature, use the equation $$R=2f$$ "The distance between the focal point and the mirror" is defined as the focal length. Therefore, the focal length is $10cm$. Since the mirror is convex, the value of the focal length is negative. Substituting this value into the equation yields $$R=2(-10cm)=-20cm$$
