In a ΔABC, if 4∠A = 3∠B = 12∠C, find ∠A?

$$\eqalign{ & 4\angle A = 3\angle B = 12\angle C \cr & A:B:C = \frac{1}{4}:\frac{1}{3}:\frac{1}{{12}} \cr & A:B:C = 3:4:1 \cr & {\text{Now}} \cr & 3x + 4x + x = 180 \cr & 8x = 180 \cr & x = \frac{{180}}{8} \cr & \angle A = 3x = \frac{{180}}{8} \times 3 = 67.5 \cr} $$