The total surface area of a cuboid of length 90 cm, breadth 50 cm and height 4 m is:

12.1 m²

We know that,

Total surface area of a cuboid = 2 × {length × breadth + length × height + breadth × height}

Given,

The length = 90cm

 breadth = 50cm

and height = 4m

The total surface area of the given cuboid = 2 × {0.9 × 0.5 + 0.9 × 4 + 0.5 × 4}

= 2 × {0.45 + 3.6 + 2}

= 2 × 6.05 = 12.1 m²