They are usually measured with milliliters; although, a half liter of milk is perfectly viable.
I would estimate around 6 because say it was 6.5 and 3 then it would around the square root of like 31 and that is rounding down a lot so we would bump it up to somewhenre around 35 so the side would be around 5.8-6
Part A: First, list multiples for each number. The multiples of 5 are: 5, 10, 15, 20, 25 30, 35, 40, 45, 50, 55, 60, etc. The multiples of 12 are: 12, 24, 36,48, 60, etc. The least common multiple is the first common multiple between the two, in this case being 60. The LCM of 5 and 12 is 60.
Part B: SImilar to above, list all factors for each number. 72: 1, 2, 3, 4, 6, 8, 9, 12, 18, 24, 36, and 72. 81: 1, 3, 9, 27, and 81. The greatest common factor is the highest common number, 9 in this case. The GCF of 72 and 81 is 9.
Part C: To rewrite, we need to take out the 9 by dividing. 72/9 is 8. 81/9 is 9. Therefore, we would get 9(8+9), to equal 153. Your answer here is 9( 8 + 9 ). Hope this helped!