Answer to Question #1194 in Geometry for MrsMaha ismail
1- if I have angle A = angle B and angle D = angle C
Prove that lines AB parallel to line DC.
A=B and C=D, and A+B+C+D=360
2A + 2 C = 360;
A+C = 180.
The sum of unilateral internal angles equals to 180°, then the lines are parallel.