<P> In mathematics , a real number is a value of a continuous quantity that can represent a distance along a line . The adjective real in this context was introduced in the 17th century by René Descartes , who distinguished between real and imaginary roots of polynomials . The real numbers include all the rational numbers , such as the integer − 5 and the fraction 4 / 3 , and all the irrational numbers , such as √ 2 ( 1.41421356 ... , the square root of 2 , an irrational algebraic number ) . Included within the irrationals are the transcendental numbers , such as π ( 3.14159265 ... ) . In addition to measuring distance , real numbers can be used to measure quantities such as time , mass , energy , velocity , and many more . </P>
<P> In mathematics , a real number is a value of a continuous quantity that can represent a distance along a line . The adjective real in this context was introduced in the 17th century by René Descartes , who distinguished between real and imaginary roots of polynomials . The real numbers include all the rational numbers , such as the integer − 5 and the fraction 4 / 3 , and all the irrational numbers , such as √ 2 ( 1.41421356 ... , the square root of 2 , an irrational algebraic number ) . Included within the irrationals are the transcendental numbers , such as π ( 3.14159265 ... ) . In addition to measuring distance , real numbers can be used to measure quantities such as time , mass , energy , velocity , and many more . </P>
square root of 9 belongs to what family of real numbers
square root of 9 belongs to what family of real numbers
rational numbers
rational numbers