Look for the largest square factor of 468. Since 468 = 36 × 13 and √36 = 6, we get √468 = 6√13. To simplify a surd, split the number under the root into a perfect-square factor and the remaining factor. Take the square root of the perfect square outside the radical. The expression is simplified when no square factor greater than 1 remains under the root. The correct answer is 6√13, which matches the calculation or reasoning shown.