A cuboid measures 8 cm by 5 cm by 3 cm. What is its total surface area?

हल

1. 01

   A cuboid has three pairs of identical faces, so the total surface area is $2(lb + bh + lh)$.

2. 02

   Here $lb = 8 \times 5 = 40$, $bh = 5 \times 3 = 15$ and $lh = 8 \times 3 = 24$.

3. 03

   Their sum is $40 + 15 + 24 = 79$, and doubling it gives $158$ cm².