A quadrilateral has all four angles of the same measure, what is the measure of each angle?

Two angles of a quadrilateral measure $55°$ each. The third angle is $140°$. What is the measure of the fourth angle?

The angles of a quadrilateral are in the following ratio. Find the measure of the four angles.

$3:5:7:9$

$\mathrm{ABCD}$ is a quadrilateral. $\mathrm{AO}$ and $\mathrm{BO}$ are the angle bisectors of angle $\mathrm{A}$ and $\mathrm{B}$ which meet at $\mathrm{O}$. If $\angle \mathrm{C}=70°,\angle \mathrm{D}=50°$, find $\angle \mathrm{AOB}$.

The value of $y°$ in the given figure is

What is the value of $a$?

Find the values of x, y and z in the diagram. Give reasons wherever necessary.