Square Roots

The square root of $x$, written $\sqrt{x}$, is the number that gives you $x$ when squared. So $\sqrt{25} = 5$ because $5^2 = 25$.

Square roots undo squaring. If you square a number and then take its square root, you get back where you started (ignoring sign complications).

In code, you'll use square roots for geometry (distance formulas), number theory (checking primes), and binary search problems. If your loop condition involves $i \times i \leq n$, you're working with square roots.