Question

Anyone who can prove it perfectly with explanation in the copy.

Answer 1

In ∆AOD and ∆BOC
OA=~ OB .........given
OD=~OC ..........given
ANGLE BOC =~ ANGLE AOD.........vertically opp angles
∆AOD =~∆BOC..........by SAS test
AD =~BC ........C.S.C.T
AD||BC