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Square Root Calculator
Square Root (√x)
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Home / Math / Square Root
Square Root (√x)
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Knowing the first few perfect squares (1, 4, 9, 16, 25, 36, 49, 64, 81, 100, 121, 144) is a superpower. It helps you estimate roots instantly and check your work.
Mathematically, x² = 25 has two solutions (+5 and -5). However, the symbol √25 usually refers to the principal (positive) root, which is just 5.
Need √50? You know it's between √49 (7) and √64 (8). Since 50 is practically 49, the answer is just a tiny bit more than 7 (like 7.07).
This is the most common error. √100 is 10, NOT 50. Square root asks "what number times itself?", not "what is half?".
You cannot find the real square root of a negative number (like √-4). That requires imaginary numbers (2i). If you get an error, check for a negative sign.
√0.9 is roughly 0.95, which is larger than 0.9. Roots of decimals less than 1 are actually bigger than the original number! It's counter-intuitive.