The two unequal diagonals of a parallelogram bisect each other at right angles. What special name is given to this parallelogram? Write the properties of a parallelogram.

In the given trapezium $LMNP$, $LM\parallel NP$. If $\angle N=100°$ and $\angle P=70°$, then find the measure of $\angle PLM$ and $\angle NML$.

$ABCD$ is a square. Its diagonal $AC$ and $BD$ intersect each other at $O$. Find the measures of $\angle CAD$and $\angle DBC$.

In the figure, $PQRS$ is a square and $PQTU$ is a rhombus. $\angle UPS=136°$. Find $x$ and $y$.

The sum of the four interior angles of a quadrilateral is_____.