Real Numbers and a Number Line

- A number a is a square root of a number b if  $\alpha^2$ = b.

-Example  $7^2$  = 49, so 7 is a square root of 49

You can use the definition above to find the exact square roots of some nonnegative numbers. You can approximate the square roots of other nonnegative numbers. 

The radical symbol $\sqrt{ }$    indicates a nonnegative square root, also called a principal square root. The expression under the radical symbol is called the radicand.  $\sqrt{a}$  

Together, the radical symbol and radicand form a radical.