The diagonals of a quadrilateral are perpendicular to each other. Is such a quadrilateral always a rhombus$?$ If your answer is 'No', draw a figure to justify your answer. 

Draw a rhombus with each side of length $3.5 \mathrm{cm}$ and one of the angles as $40°$.

Draw a rhombus $\mathrm{ABCD}$, if $\mathrm{AB}=6 \mathrm{cm}\text{ and }\mathrm{AC}=5 \mathrm{cm}$.

$ABCD$ is a rhombus and its diagonals intersect at $O.$ Is $\Delta BOC\cong \Delta DOC ?$ State the congruence condition used$?$

$ABCD$ is a rhombus and its diagonals intersect at $\mathrm{O}$. State, if $\angle \mathrm{BCO}=\angle \mathrm{DCO}$.