This is true. The closer to the mean that a value is, the more likely it is to occur.
In this case, two and three standard deviations away are both fairly unlikely, however, two is still more likely to occur than three.
First angle is x
x + (x + 45) + 2x = 180
4x + 45 = 180
4x = 180 - 45 = 135
x = 135 divided by 4
x = 33.75
first angle 33.75
second angle 78.75
third angle 67.5
checking
33.75 + 78.75 + 67.5 = 180
3x + 24 = (3)(x) + (3)(8)
You can see that there is multiplier 3 near x and 8. You can factor it and make
3x + 24 = 3(x + 8)
So, the answer is 3. Hope this helps!