Find the area of a parallelepiped (that is, the sum without edges) if its dimensions are 5 cm, 6 cm and 3 cm.

In order to determine the total surface area of a parallelepiped (i.e. the total surface area of all its faces), it is necessary to add the areas of all faces of the rectangular parallelepiped. Each face is based on a rectangle. Therefore, to calculate the total surface, it is enough to use the following formula:

S = 2 * (a * b + b * c + a * c),

where a, b, c – parallelepiped measurements.

Then we get:

S = 2 * (5 * 6 + 5 * 3 + 6 * 3) = 2 * 63 = 126 (cm 2).

Answer: S = 126 cm 2.