1. Squares of Numbers Greater than 20 Return to Table of Contents

2. Think about this... What about larger numbers? How do you find ?

3. It helps to know the squares of larger numbers such as the multiples of tens. 10 2 = 100 20 2 = 400 30 2 = 900 40 2 = 1600 50 2 = 2500 60 2 = 3600 70 2 = 4900 80 2 = 6400 90 2 = 8100 100 2 = 10000 What pattern do you notice?

5. For larger numbers, determine between which two multiples of ten the number lies. 10 2 = 1001 2 = 1 20 2 = 4002 2 = 4 30 2 = 9003 2 = 9 40 2 = 16004 2 = 16 50 2 = 25005 2 = 25 60 2 = 36006 2 = 36 70 2 = 49007 2 = 49 80 2 = 64008 2 = 64 90 2 = 81009 2 = 81 100 2 = 10000 10 2 = 100 Next, look at the ones digit to determine the ones digit of your square root.

6. 2809 Examples: Lies between 2500 & 3600 (50 and 60) Ends in nine so square root ends in 3 or 7 Try 53 then 57 53 2 = 2809 Lies between 6400 and 8100 (80 and 90) Ends in 4 so square root ends in 2 or 8 Try 82 then 88 82 2 = 6724 NO! 88 2 = 7744 7744

7. 15 Find.

8. 42 16 Find.

9. 17 Find.

10. Simplifying Perfect Square Radical Expressions Return to Table of Contents

11. Square Root Of A Number Recall: If b 2 = a, then b is a square root of a. Example: If 4 2 = 16, then 4 is a square root of 16 What is a square root of 25? 64? 100? 5 8 10

12. Square Root Of A Number Square roots are written with a radical symbol Positive square root: = 4 Negative square root:- = - 4 Positive & negative square roots: = 4 Negative numbers have no real square roots no real roots because there is no real number that, when squared, would equal -16.

13. Is there a difference between Which expression has no real roots? & Evaluate the expressions: ?

14. is not real Evaluate the expression