The perimeter of square $ABCD$ is $16 \, cm$,then $ar(ABCD) = \ldots \ldots \ldots \, cm^2$.

$(1)$ $A$ quadrilateral in which only one pair of opposite sides are parallel is a $\ldots \ldots \ldots$.
$(2)$ The diagonals of a rectangle are $\ldots \ldots \ldots$.

In quadrilateral $ABCD$,$\angle A : \angle B : \angle C : \angle D = 1 : 4 : 2 : 2$. Find the measure of each angle of the quadrilateral.

Can all the angles of a quadrilateral be right angles? Give reason for your answer.

Can all the four angles of a quadrilateral be obtuse angles? Give reason for your answer.

Angles of a quadrilateral are in the ratio $3:4:4:7$. Find all the angles of the quadrilateral.