SInce it shown in the figure the angle C and angle D are equal
angle C = Angle D = 50°
The angle A and angle B are also let say x°
so,
Angle A = Angle B = x°
Since sum of all angle in a quadrilateral (trapezium) =360°
Thus,
[tex]\begin{gathered} \angle A\text{ + }\angle B\text{ + }\angle C\text{ + }\angle D=360^{\circ} \\ x\text{ + x + 50 + 50}=360 \\ 2x\text{ + 100 = 360} \\ 2x\text{ = 360-100} \\ 2x\text{ = 260} \\ x=130^{\circ} \\ \text{ So, }\angle A\text{ }=130^{\circ}\text{ and }\angle B\text{ }=130^{\circ} \end{gathered}[/tex]