A polygon in which at least one interior angle is greater than $180°$ is called convex polygon.

$6$ sided polygon is called hexagon.

Sum of all interior angles of a quadrilateral is $180°$.

Each interior angle of a $n$-sided regular polygon is $\frac{(2n-4)\times 90°}{n}$

The diagonals of a parallelogram bisect each other at right angles.

The opposite angles of a parallelogram are of equal measure.

The diagonals of a rhombus bisect the angles of a rhombus.

The diagonals of a square are not equal.

Co-interior angles of a parallelogram are supplementary.