ten-sided die

Ten-sided dice are often used in role-playing games, such as Dungeons and Dragons, to get random decimal numbers, such as percentages. Each die is generally a decahedron called a pentagonal trapezohedron with 10 kite-shaped faces, to improve rolling the edges are rounded or sub-faces are introduced by truncation. The basic shape is two five-sided pyramids stuck together on their pentagonal face, one rotated by 36 degrees. Opposite sides on such a die total nine. Each face has two long sides and two short sides. The five odd-numbered faces meet at the common vertex of their long sides. The five even-numbered faces meet at the common vertex of their long sides. There seems to be a standard configuration for the numbers on 10-sided dice. If one holds such a die between one's fingers at two of the vertices such that the even numbers are on top, and reads the numbers from left to right in a zigzag pattern, the sequence obtained is 0, 7, 4, 1, 6, 9, 2, 5, 8, 3, and back to 0. (In this position, odd numbers appear upside-down.) These dice are often sold in pairs for use as a percentile die. One die will be marked by tens from 00 through 90, and the other will have units from 0 to 9. The use of such markings is to generate random numbers from 00 to 99, also known as percentile; however, in practice, two dice of different colours may prove easier to read.

Ten-sided Die

See also