Question

meaning of allied angles ànd its properties

Answer 1

Two parallel lines intersected by a transversal line, form all sorts of angles that can be paired by their comparable properties.
For example, v and u are equal; and so are x and z. In fact they are all equal except for z and v (or u and x).
These two pairs are called allied angles and are supplementary angles meaning that their sum is equal to 180°.