1. 1.2 Square Roots of Non-Perfect Squares
Learning Objective: Can I determine the square root of a non-perfect square?

2. Lesson Goals
1. Approximate the square roots of decimals and fractions of nonperfect
squares.
2. Use the Pythagorean Theorem to find the missing side of a right
triangle.

3. Introduction... Many fractions and decimals are not perfect squares.
A fraction or decimal that is not a perfect square is called a non-perfect square.
The square roots of these numbers do not work out evenly!
Vocabulary: A non-perfect square is a number that cannot be written as the product of two equal numbers.
How can we estimate a square root of a decimal that is a non-perfect square?

4. Here are 2 strategies...
Ask yourself: “Which 2 perfect squares are closest to 7.5?”
7.5 2 3
2.5
7.5 is closer to 9 than to 4, so is closer to 3 than to 2.
What would be a good approximation?

5. Strategy #2... Use a calculator! 
But, of course, you must be able to do both on a test!

6. We call these 2 numbers ‘benchmarks’.
Example #1
Determine an approximate value of each square root.
We call these 2 numbers ‘benchmarks’.
close to 9
close to 4 ~
What does this mean?

7. Of course, you can always use a calculator to CHECK your answer!
Example #2
Determine an approximate value of each square root.
Your benchmarks!
0.40
0.30
0.20
0.25
0.36
Of course, you can always use a calculator to CHECK your answer!

8. Unit 1 Assignment 2
p. 18 #4abcd, 5abc, 6, 7abcd, 11aceg, 13, 15, 16, 20