The height of a parallelepiped rectangle is 20 cm, 5 cm more than its width and 3 times

The height of a parallelepiped rectangle is 20 cm, 5 cm more than its width and 3 times less than its length. Calculate the surface area of the parallelepiped.

Find the length and width of the parallelepiped:
a = c – 5 = 20 – 5 = 15 cm.
b = c * 3 = 20 * 3 = 60 cm.
The surface area of a rectangular parallelepiped is equal to the sum of the areas of its faces:
S = (a * b + a * c + b * c) * 2 = (15 * 60 + 15 * 20 + 60 * 20) * 2 = (900 + 300 + 1200) * 2 = 2400 * 2 = 4800 cm².
Answer: the surface area is 4800 cm².