Edge of the cube = 20 cm (given) ∴ Diameter of the circle = Edge of the Cube = 20 cm So, radius of the circle (r) = 10 cm Now, Area of the cube = 6 a2 = 6 x 20 x 20 = 2400 cm2 Area of one circle = πr2=
22
7
x 10 x 10 cm2 = 314.28 cm2 Area of 6 circles = 6 x πr2 = 6 x 314.28 cm2 = 1885.71 cm2 ∴ Total unpainted surface of the cube = (2400 - 1885.71) cm2 = 514.28 cm2