1. Objective
The learner will calculate, estimate, and use square roots

2. Why?
You may need to find out the value of irrational numbers.

3. Finding and Estimating Square Roots Pages 524 - 528
Lesson
Finding and Estimating Square Roots
Pages

4. Video
Squares & Square Roots

5. Every positive number has two square roots, a positive and a negative.
The number a is a square root of b if a² = b.
Example: 4² = 16 and (-4)² = 16, so 4 and -4 are square roots of 16.
A radical symbol √ indicates a square root.

6. The expression √16 means the positive, or principal square root, of 16, which would be 4.
The expression - √16 means the negative square root of 16, which would be -4.
The expression under the radical sign is a radicand.
You can use the symbol ± to indicate both square roots.

7. The squares of integers are called perfect squares.
Consecutive integers
Consecutive perfect
squares
You can estimate square roots by using perfect squares.

8. The formula d = √x² + (2x)² gives the length d of each wire for a tower. Find the length of the wire if x = 12 feet.
d = √12² + (2 * 12)² (Substitute)
d = √ (Simplify)
d = √720
d ≈ 26.8
The wire is approx feet long.

9. Examples in Text
Page 120