SQUARE ROOTS

Concept: The Square Root of a number is the number that when multiplied by itself equals the given number. The symbol for square root is . To find the square root of a certain number, ask yourself, “What number times itself equals this number?”

Example:

Solve: ? This problem asks, “What is the square root of 25?” Ask yourself, “What number times itself equals 25?” You know from your Multiplication Tables that 5 x 5 = 25, so the square root of 25 is 5, or .

Memorize the following list of squares to help you find square roots.

12 = 1 42 = 16 72 = 49 102 = 100

22 = 4 52 = 25 82 = 64 112 = 121

32 = 9 62 = 36 92 = 81 122 = 144

More Examples:

Concept Continued: Most square roots are not whole numbers. You can use the list of common squares above to help you estimate an answer, or you can find a more exact answer using your calculator.

Still Another Example:

Solve: ? This problem asks, “What is the square root of 55?” Ask yourself, “What number times itself equals 55?” You know that 7 x 7 = 49 and 8 x 8 = 64. So, since 55 is between 49 and 64, the square root of 55 must be between 7 and 8.

If we wish to have an exact number rather than an approximate number, we can use a calculator to determine that the exact square root of 55 is 7.41, or .