# A child of height 2.4ft is standing in front of the mirro.his brother of height 4.8ft is standing behind him.the minimum height of the mirror required so that the child can completely see his own image n his brothers image in the mirror is?

Magnification of plane mirror is $1$ because image height and object height are the same.
Here is we consider that the mirror was initially $2.4 f t$ high,so that the child was only able to see his full image,then the mirror needs to be $4.8 f t$ long so that the child can look up,where he can see the image of his brother's upper part of the body,which is visible above him.