单选题In quadrilateral ABCD, ∠A+∠C is 2 times ∠B+∠D. If ∠A=70, then ∠B= ______.A 60B 80C 120D 240E It cannot be determined from the information given
题目
单选题
In quadrilateral ABCD, ∠A+∠C is 2 times ∠B+∠D. If ∠A=70, then ∠B= ______.
A
60
B
80
C
120
D
240
E
It cannot be determined from the information given