Question

在四边形ABCD中,若∠A+∠C=180°,且∠B:∠C:∠D=2:3:6,则∠A=

Answer 1

1.A+B+C+D=360

2.A+C=180

3.B:C:D=2:3:6

1,2,3式联解得出结论,A=112.5