The Total solution for NCERT class 6-12
Two lines l1 andl2 intersect eachother at O∴Vertically opposite angles are equal,∴ y =25° and x = zNow 25° + x = 180° (Linear pair)⇒ x=180°-25°= 155°∴ z = x= 155°Hence x = 155°, y = 25°, z = 155°