Question

find x and y and then solve that AB II CD and also show that if two lines intersect each other then prove that vertically opposite angles are equal ​

Answer 1

If two lines i.e. AB & CD intersect each other. They have two pair of opp. angles.

i.e.

∠AOC,∠DOB,∠AOB,∠COB.

To prove :- ∠AOC=∠DOB & ∠AOD=∠COB

Proof :-

∠AOC+∠AOD=180

∘

[linear pair] ___(1)

∠AOD+∠BOD=180

∘

[linear pair] ___(2)

from eq. (1) & (2)

∠AOC+∠AOD=∠AOD+∠BOD

i.e. [∠AOC=∠BOD]

Similarly [∠AOD=∠COB] Hence proved.

Answer 2

Answer:

AB is parallel to CD

it's according to the theorem

read above the full theorem