After the surface area of a cube is painted the cube is cut into 64 smaller cubes of same dimensions. How many have no face painted? 1 face painted? 2 faces painted? 3 faces painted?
Note that lateral surface area of a cylinder is the circumference of base x height of cylinder. Can we write lateral surface area of a cuboid as perimeter of base x height of cuboid?
Total surface area = 2[lb x bh + hl]
But bottom is not painted.
i.e. Area not painted = lb
∴ Total S.A. to be painted = 2(bh + hl) + bh
= 2[(2 x 1.5) + (1.5 x 1)] + (2 x 1) m2
= 2[3 + 1.5] + 2 m2
= 2[4.5] + 2 m2
= 9 + 2 m2
= 11 m2