3-9 Finding Square Roots Warm Up Pre-Algebra 3-9 Finding Square Roots Hmwk & calculator outt Warm Up Find the two square roots of each number. Evaluate each expression. 1. 144 2. 256 ±12 ±16 3. 8+ 144 4. 7 289 20 119

Finding Square Roots Learn to estimate square roots to a given number of decimal places and solve problems using square roots.

Each square root is between two integers. Name the integers. Think: What are perfect squares close to 55? A. 55 72 = 49 82 = 64 55 is between 7 and 8.

Each square root is between two integers. Name the integers. Think: What are perfect squares close to 90? B. – 90 –92 = 81 –102 = 100 90 – is between –9 and –10.

Each square root is between two integers. Name the integers. Think: What are perfect squares close to 80? A. 80 82 = 64 92 = 81 is between 8 and 9. 80

Each square root is between two integers. Name the integers. Think: What are perfect squares close to 45? B. – 45 –62 = 36 –72 = 49 45 – is between –6 and –7.

Use a calculator to find 500. Round to the nearest tenth. Additional Examples 3: Using a Calculator to Estimate the Value of a Square Root Use a calculator to find 500. Round to the nearest tenth. Using a calculator, 500 ≈ 22.36067977…. Rounded, 500 is 22.4.

Use a calculator to find 200. Round to the nearest tenth. Try This: Example 3 Use a calculator to find 200. Round to the nearest tenth. Using a calculator, 200 ≈ 14.14213562…. Rounded, 200 is 14.1.

You want to sew a fringe on a square tablecloth with an area of 500 square inches. Calculate the length of each side of the tablecloth and the length of fringe you will need to the nearest tenth of an inch. Understand the Problem First find the length of a side. Then you can use the length of a side to find the perimeter, the length of fringe around the tablecloth.

Try This: Example 2 Continued Look Back The length 63.2 feet divided by 4 is 15.8 feet. A 15.8 foot square has an area of 249.64 square feet, which is close to 250, so the answers are reasonable.

Lesson Quiz Each square root is between two integers. Name the two integers. 1. 27 2. – 456 5 and 6 –22 and –21 Use a calculator to find each value. Round to the nearest tenth. 3. 89 4. 1223 9.4 35.0 5. A square field has an area of 2000 square feet. To the nearest foot, how much fencing would be needed to enclose the field? 179 ft