Question no 4
in parallelogram ABCD
take triangle ABC
we know that O is the mid point of AC therefore
by mid point theorem P is the mid point of AB
there fore AP=PB
SIMILARLY Q is the mid point of DC
therefore DQ=QC
since AB=DC
AP=PB=DQ=QC
in triangle AOP and COQ
OA =OC .......{ O is the midpoint of AC }
AP=QC........{PROVED ABOVE}
<OAP=<OCQ.....[ALT INT ANG] by SAS congruence the triangles are congruent
by CPCT OP=OQ
take triangle ABC
we know that O is the mid point of AC therefore
by mid point theorem P is the mid point of AB
there fore AP=PB
SIMILARLY Q is the mid point of DC
therefore DQ=QC
since AB=DC
AP=PB=DQ=QC
in triangle AOP and COQ
OA =OC .......{ O is the midpoint of AC }
AP=QC........{PROVED ABOVE}
<OAP=<OCQ.....[ALT INT ANG] by SAS congruence the triangles are congruent
by CPCT OP=OQ