A cube whose edge is 10 cm long, has circles on each of its faces painted red. What is the total area of the unpainted surface of the cube if the circles are of the largest possible areas? (Take \(\pi \) = 3.14 )

129 cm²

Total surface area of cube =  6 × side² = 6 × 100 = 600

A cube has 6 faces, therefore there are total 6 circles on the surface of cube.

Area of one circle = \(\pi \) r² = \(\pi \) 5²  = 25\(\pi \)

Area of six circles = 6 × 25\(\pi \) = 150 \(\pi \)

Area of unpainted surface of the cube = Total surface area of cube - area of six circles

= 600 - 150 \(\pi \) = 600 - 150(3.14) = 600 - 471 = 129 cm²