Answer
$2^{3}$ * $3^{2}$
Work Step by Step
72
Try to divide 72 by the first prime number 2
72 = 36 * 2
Try to divide 36 by the first prime number 2
36 = 18 * 2
Try to divide 18 by the first prime number 2
18 = 9 * 2
Try to divide 9 by the prime number 3
9 = 3 * 3
So, 72 = 2 * 2* 2 *3*3
Because all factors are prime, the prime factorization of 72 is
2 * 2* 2 *3*3 = $2^{3}$ * $3^{2}$