Question

Calculate the value of the unknown angle

Answer 1

Angle B = Angle D
Angle D = 80
Angle A+B+C+D = 360
Angle C = Angle A
Angle A = 2x

80+80+2x+2x = 360
160+4x=360
4x=360-160
4x=200
X=200/4
x=50

Answer 2

80+2x=180°{co-interior angle}

2x=180-80

2x=100

x=50°

hope it helps.