1. Notes 2.1 and 2.2 LOOKING FOR SQUARES AND SQUARE ROOTS

2. Lengths of squares. The area of a square is calculated by multiplying two sides together. Therefore, a square that has an area of 4 cm 2 has a length of 2 cm and a width of 2 cm. Another way to say this is that the two numbers that multiply together to make 4 are 2 and 2. How can you use the area of a square to find the length of the side

3. Square roots Since 2 times 2 is equal to 4, then 2 is the square root of 4. Another way to say this is 2 times itself is equal to 4, therefore 2 is a square root of 4 Square roots can be either negative or positive because ; -2 times -2 is equal to 4 just like 2 times 2 is 4. Every positive number has 2 square roots, but the number 0 only has 1 square root, 0 What is a square root? Are square roots negative or positive?

4. Notation and finding square roots. This is the symbol for square root. What it means is that you are looking for a number, when multiplied by itself equals the number inside the square root sign. To find a square root, think to yourself “what number multiplied by itself equals that number. For example what is the square root of 100? Think “What number multiplied by itself equals 100?’ The answer is 10 of course. To find a square root that is not a whole number you have to estimate to start. For example: what is the square root of 5? 5 is between the two numbers that we know the square roots of, 4 and 9. The square root of 4 is 2, but 5 is greater than 4 so its square root must be greater than 2. However, 5 is less than 9 so the square root of 5 must be less than 3, but is must be closer to 2 than 3 because 5 is closer to 4. So we start with 2.1 and multiply it by 2.1, that equals 4.41, so it must be greater than 2.1, so lets try 2.2 2.2 times 2.2 is 4.84 so we are closer but not there yet. Let’s try 2.24. 2.24 times 2.24 is 5.01, which is very close to 5. Of course if you have a calculator you can use the square root key and find that the square root of 5 is 2.2360679 How do we show square roots How do you find a square root? How do you find a square root that is not a whole number?