Which of the following is the simplified form of the square root of 72?

Correct answer to question 11 (Mathematics Knowledge): 6 root 2

Method

Pull out the largest perfect square: 72 is 36 x 2, and the root of 36 is 6, giving 6 root 2. The choices 3 root 8 and 2 root 18 both equal the same number but are not fully simplified, since 8 and 18 still contain square factors.