A rectangular cardboard of dimensions 20 m × 10 m is placed on a table. 4 squares of side 2.5 m are cut out from the corners and the 4 sides are folded . Find the surface area of the resulting figure which is to be painted on all the sides.
175
A square of side 2.5 m is cut off from all the corners. Therefore, the length of a rectangular sheet changes to 15 m (20 - 2 × 2.5) and breadth to 5 m (10 - 2 × 2.5)
Therefore, the surface area of the resulting figure = sum of areas of I, II, III, IV, V
= (15 × 2.5) + (5 × 2.5) + (15 × 2.5) + (5 × 2.5) + (15 × 5) = 175 m2