Page:The algebra of Mohammed ben Musa (IA algebraofmohamme00khuwrich).pdf/28

 (6)

A root is any quantity which is to be multiplied by itself, consisting of units, or numbers ascending, or fractions descending.*

A square is the whole amount of the root multiplied by itself.

A simple number is any number which may be pronounced without reference to root or square.

A number belonging to one of these three classes may be equal to a number of another class; you may say, for instance, “squares are equal to roots,” or "squares are equal to numbers,” or “roots are equal to numbers.”+

Of the case in which squares are equal to roots, this is an example. “A square is equal to five roots of the same;"++ the root of the square is five, and the square is twenty-five, which is equal to five times its root.

So you say, "one third of the square is equal to four roots;"§ then the whole square is equal to twelve roots; that is a hundred and forty-four; and its root is twelve.

Or you say, “five squares are equal to ten roots;”|| then one square is equal to two roots; the root of the square is two, and its square is four.

unknown quantity.
 * By the word root, is meant the simple power of the