The little ² just means "times itself". So x² is x × x — and that's exactly the area of a square whose side is x. A square 5 across holds 5 × 5 = 25 squares inside. That's the whole picture behind a quadratic.
Squaring, and Going Backwards
If someone hands you the side, finding the area is easy: square it. But a quadratic asks the reverse question — "I know the area, what was the side?" To go that way you need the operation that undoes squaring, and that's the square root, written √. Set the square's area to 36 in the toy and the side comes out 6, because 6 × 6 = 36. So x² = 36 means x = √36 = 6.
Why Square root, and Why √36 = 6
"Root" is just the old word for the side that the square grew from. Asking √36 is asking "what number, times itself, makes 36?" — and that's 6. You're not learning a brand-new trick; you're reversing the squaring you already know, the same way subtracting reverses adding.
Where This Is Heading
Linear equations were a balance scale — undo with inverse operations. A quadratic is the same idea with one new inverse: squaring is undone by square-rooting. Get that x² = k → x = √k picture solid here, and the method on the next rung is barely a step further.