Finding the Angle Measures of Intersecting Lines

In the accompanying diagram, two lines intersect at point O, creating four angles: ∠AOB, ∠BOC, ∠COD, and ∠DOA. If the measure of angle ∠AOB is given as $x$ degrees, and it is known that the measure of angle ∠COD is twice that of ∠AOB, what is the measure of the angle ∠DOA?

Also, if the sum of angle ∠BOC and angle ∠DOA is equal to $180^{ ext{o}}$, what is the value of $x$?

Assume that all angles are measured in degrees.