In the given figure, find the value of $x$.

    

In the given figure, rays $AB$ and $CD$ intersect at $O$.

Determine $y°$ when $x=60°$. (Answer should be the value of $y$ without degree symbol)

In the given figure, rays $AB$ and $CD$ intersect at $O$.

Determine $x$ when $y=40°$.

In the given figure, lines $AB, CD$ and $EF$ intersect at $O$. Find the measures of $\angle AOC, \angle COF, \angle DOE$ and $\angle BOF$.

In the given figure, lines $AB$ and $CD$ intersect at $O$. If $\angle AOC+\angle BOE=70°$ and $\angle BOD=40°$, find $\angle BOE$ and reflex $\angle COE$.

Say true or false: 
If two adjacent angles are equal, then each angle measures $90°$.

If angles forming a linear pair are equal, then each of these angles is of measure $90°$.