Question 347430
We can deduce these algebraic facts from yur statements...
b + a = 180
b = 4c
c + a = 90
If we substitute 4c for b in the first equation, we get
4c + a = 180
c + a = 90
Now subtract equations and get
3c = 90
c = 30
b = 120
a = 60
and all checks out.