Using ruler and a compass only construct a semi-circle with diameter $BC=7\,\text{cm}$. Locate a point $A$ on the circumference of the semicircle such that $A$ is equidistant from $B$ and $C$. Complete the cyclic quadrilateral $\text{ABCD}$, such that $D$ is equidistant from $\text{AB}$ and $\text{BC}$. Measure $\angle \text{ADC}$ and write it down.