How many diagonals are there for a decagon $(10$-sided polygon$)$?

In the given figure, $ABCD$ is a square. Find the measure of $\angle CAD$.

The following figure $\mathrm{R}\mathrm{U}\mathrm{N}\mathrm{S}$ is a parallelogram, Find $\mathrm{x}$ and $\mathrm{y}$. (Length are in $\mathrm{c}\mathrm{m}$)