## Intermediate Algebra (6th Edition)

Numbers such as 1, 4, 9, and 25 are called perfect squares because we get a whole number when we take the square root of these numbers. For example, $\sqrt 25=5$, because $5^{2}=5\times5=25$. Numbers such as 1, 8, 27, and 125 are called perfect cubes because we get a whole number when we take the cube root of these numbers. For example, $\sqrt 125=5$, because $5^{3}=5\times5\times5=125$.