area of a square = side^2
area of a cube = 6 x side^2
let the side be a .
6a^2 = 600
=> a^2 = 600/6
=> a^2 = 100
Hence the area of one of its faces is 100 square inches.
or in plain terms without using those formulas,
6 faces of the cube have 600 square inches
=> 1 face of the cube has 600/6 = 100 square inches
