Given that, magnification is 3 times enlarged and virtual image. So m=+3(because +represents virtual image and 3 tells us that the height of image is 3 times that of object. Since, m=-(v/u) 3 = -(v/-10cm) v=30cm By mirror formula, 1/f = 1/v +1/u = 1/30 + 1/-10 =-2/30 f=-15cm Since R=2f=2x(-15cm)=-30cm Ans: The Radius of curvature measures -30cm