Answer:
36
Explanation:
GCF or greatest common factor is the greater/biggest number that can factor for both numbers. To find GCF, you need to make factor of both number
72- 2 * 2 * 2 * 3 * 3 = 2^3 * 3^2
36= 2 * 2 * 3 * 3 = 2^2 * 3^2
After this, you can compare the factor of both numbers. Both numbers can be divided by 2, but 36 can be divided 2 times while 72 can be divided 3 times. In this case, you take the lowest number which is 2. Both numbers can be divided by 3^2 so you can take it whole.
The factor will be: 2^2 * 3 *2= 4 * 9= 36