Question

Solve no 9 pls.pls solve it fast

Answer 1

In triangle AOD and COB
AO=OB. -(1)
CO=OD. -(2)
/_COB=/_AOD

BY SAS CONGRUENCY CRITERIAN
∆AOD congruent ∆BOC

similarly
in ∆AOC and ∆BOD
AO=OB. -(3)
OC=OD. -(4)
/_AOC=/_BOD

∆ AOC congruent to ∆BOD

by SAS congruency criterion.

(◆A)

since ∆ AOC congruent to ∆BOD

so AC=BD

(◆B)
/_CAO=/_CAB
/_ABD=/_OBD

since ∆ AOC congruent to ∆BOD

so /_ CAO=/_DBO

(◆C)
as angle /_CAO=/_DBO
similarly /_ABC=/_BAD

and both of these angles are alternate angles so line containing this angle will be parallel.

(◆D)
since ∆AOD congruent ∆BOC
hence AD=BC

(●●cooresponding part of congruent triangle)