<PRE><B>Question 443054</B>
We know that A + B +C = 180  
They tell us:
B = 4A
C = 5A - 12

Then A + 4A + (5A-12) = 180
10A - 12 = 180
10A = 192
A = 19.2º

B = 4(19.2) = 76.8º

19.2 + 76.8 + C = 180

96 + C = 180

C = 180 - 96

C = 84º


The angles are 19.2, 76.8, 84.

What you asked for, Angle A, is 19.2º.

Hope this helped!</PRE>