81, 84, 87
There are infinitely many solutions to this: 91, 92, 90.5, etc.
55, 60, 65
109 whole numbers greater than 9 and less than 999 are multiples of 9
72
Obtuse angle
81,84,87,90
Nine.
36 and 42
81, 84, 87.
24, 36, 48
The following numbers are multiples of 4: 52 56 60 64 68
18, 21, 24, 27.