Why do you learn square roots? Square roots are used to find the side length of a square when you know the area of the square. Square Root of a Number If b2 = a, then b is a square root of a. Example: 32 = 9 and (-3)2 = 9, so 3 and -3 are square roots of 9. All positive real numbers have two square roots, a positive square root (also called principal square root) and a negative square root.

Perfect Squares The square of an integer is called a perfect square. Example: 42 = 16, therefore 16 is a perfect square. A perfect square is a number whose positive square root is a whole number. Example: = 4

Perfect Squares 64 225 1 81 4 400 100 9 121 625 16 144 25 169 36 196 49

Perfect Squares = 1 = 8 = 15 = 2 = 9 = 20 = 10 = 3 = 30 = 11 = 4 = 12 = 5 = 13 = 6 = 14 = 7

= 10 = 11 = 2 = 1 = 15 = 8 = 9 = 20 = 3 = 4 = 30 = 12 = 13 = 5 = 14 = 6 = 7