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Lesson 94: Intro to Square Roots
Square roots come up again and again in math. It's very important to fully understand how they work. The concept is easy to understand.
In math, taking the square root of a number is the opposite of squaring it. When we square a number, we multiply it by itself. When we take the square root, we compute what number times itself will equal that number.
For example, the square of 4 is 16, because 4 x 4 is 16. We could also write 42 = 16. To figure out the square root of 16, we just calculate what number times itself equal 16. Of course the answer is 4. We can represent this like this: √16 = 4. You'll often see a line from the symbol extending over the top of the number.
Let's just try a few more. √25 = 5, because 5 x 5 = 25. √169 = 13, because 13 x 13 = 169. All of the numbers that we've worked with are called perfect squares. That's because when we computed the square root, the answer was a whole number. If we used our calculator to help us figure out √(53.29), we would see that the answer was 7.3. That means that 53.29 is not a perfect square.
Let's look at a simpler number: √17. It can be hard to figure out the answer without a calculator. If we compute it on a calculator, we will get an answer with many decimal places. Usually we'd round our answer to one or two decimal places, and write 4.12.
You'll work much more with square roots later. For now, make sure that you understand the concept, and memorize the perfect squares through at least 100 which are 4, 9, 16, 25, 36, 49, 64, 81, 100.
Remember that you can ask a math question if you have additional questions about a topic, or you can contact me if you have any comments or suggestions for this site.