Given a rectangular parallelepiped, its length is 12 cm, width is 7 cm, height is 3 cm, find the surface area of the parallelepiped.

Find the area of the horizontal surface of the parallelepiped.

We multiply the length by the width.

12 * 7 = 84 cm2

Since he has 2 such parties, their sum of areas will be:

2 * 84 = 168 cm2

Determine the vertical surface area.

We multiply the height by the length.

12 * 3 = 36 cm2

Square of two sides:

36 * 2 = 72 cm2

Find the area of the two remaining sides.

We multiply the number of sides by the product of width and height.

2 * 7 * 3 = 2 * 21 = 42 cm2

The total surface area will be equal to:

168 + 72 + 42 = 282 cm2

Answer: 282 cm2