77/21 = 3.6 recurring (that is, 3.6666...)
38.5
The GCF of 21, 77, and 84 is 7. First you have to find the lowest common factor, that is able to be divided by all the numbers. E.g. 7 *21/7=3 *77/7=11 *84/7=12 3 and 11 are prime numbers and can therefore not be any divided further. Therefore the answer is 7.
12.8333
0.8182
77
0.8851
15.4
0.0349
77
77
77
77