Answer:
because their principal square roots are also positive integers, square roots of numbers which are not perfect squares like 2 are irrational
step by step:
The square of a number is the number you get ehen you multiply that bumber by itself. so if n is a number then nxn = n2 is the 'square of n' it is called that because the area of a square whose edge lengh is n units is n2 square units
perfect square numbers are the numbers which are ths squares of the positive integers
