Let each copy be x, then angle B=x angle C=2x angle D=3x.

Then angle A+ angle C = 180 degrees, then angle A= 180- angle C= 180-2x.

Then angle a+ angle C+ angle B+ angle D=360.

Then 180-2x+2x+3x+x=360.

The solution is x=45.

Angle c = 2x = 2 * 45 = 90.

Then angle A= 180- angle c = 90.

Quadrilateral internal angle sum 360

Angle AC and stomach 180, then the sum of angle BD is also 180.

Regardless of angle c, let's look at angle BD. Looking at the topic, we know that the ratio of angle B to angle D is 1: 3. That is to say, if 180 is divided into four parts, the angle B occupies one part and the angle D occupies three parts.

The calculate angle b of division is 45,

The angle C is twice that of the angle B, so the angle C is 90 degrees.

180-90

Is the degree of angle a.