You are given a rectangular parallelepiped. Calculate the length of its diagonal if its linear dimensions, a = 3cm, b = 4cm, c = 5cm?

In a rectangular parallelepiped, the diagonals are equal and their length is found by the formula:
d² = a² + b² + c².
With the data on the condition of the linear dimensions of the parallelogram, we get:
d² = 9 + 16 +25 = 50;
d = √50 = 5√2 (cm).
Answer: 5√2 cm is the length of the diagonal of the parallelogram.