Question

O is  a point inside a rhombus ABCD such that BO = DO.

Prove that AO and CO are in the same straight Line.

Answer 1

In triangle aob and cob
         ab=bc (in a rhombus all sides are equal)
         ob=ob (common side)
         ANG. aob= ANG. cob=90°
therefore by rhs congruency the triangles are equal
 cpct= ao=co