Question

In a quadrilateral ABCD, side AD is parallel to side BC. If Angle A: Angle B= 2:3 and Angle C: Angle D =4:5, find each angle of the quadrilateral ABCD.

Answer 1

2x+3X= 180°
5x= 180
X = 180/5= 36
than, 2x= 36×2= 72°, 3x= 3×36=108°
again,
4x+5x= 180
9x=180
X= 180/9=20
than,4x= 4×20=80°,5x= 5×20= 100°