The flatworms, or Platyhelminthes, Plathelminthes, or platyhelminths (from the Greek ÏÎ»Î±ÏÏ, platy, meaning flat and á¼Î»Î¼Î¹Î½Ï (root: á¼Î»Î¼Î¹Î½Î¸-), helminth- , meaning worm) are a phylum of relatively simple bilaterian, unsegmented, soft-bodied invertebrates.hey have about 11,000 species, more than all other platyhelminthes combined, and second only to roundworms among parasites on metazoans. Adults usually have two holdfasts, a ring around the mouth and a larger sucker midway along what would be the underside in a free-living flatworm.
square root. (MATHEMATICS) each positive number has another number that, when multiplied times itself, equals that number. So, for example, 4 has a square root of 2 (2 x 2 = 4). The square root of a negative number is an imaginary number. Imaginary numbers are not, by themselves, useful solutions to math problems; but they can be used to find them. BILL: Anna, we have a rectangle that's 3 x as long as it is wide, and it encloses an area of 300 square meters.
The mathematical expression The (principal) square root of x. In mathematics, a square root of a number a is a number y such that y2 = a, in other words, a number y whose square (the result of multiplying the number by itself, or y Ã y) is a. For example, 4 and â4 are square roots of 16 because 42 = (â4)2 = 16. Every non-negative real number a has a unique non-negative square root, called the principal square root, which is denoted by âa, where â is called the radical sign or radix. For example, the principal square root of 9 is 3, denoted â9 = 3, because 32 = 3 Ã 3 = 9 and 3 is non-negative.