Draw a circle of radius $3$ $\mathrm{cm}$. Name the centre $\mathrm{O}$. Draw a diameter and name the endpoints $\mathrm{P}$ and $\mathrm{Q}$. Mark three points $\mathrm{A}, \mathrm{B}$and$\mathrm{C}$ such that $\mathrm{A}$ is inside the circle,$\mathbf{ }\mathrm{B}$ is on the circle and $\mathrm{C}$ is outside the circle. Join $\mathrm{OA},$$\mathrm{OB} \mathrm{and} \mathrm{OC}$. Also find the lengths of$\overline{\mathrm{PQ} }, \overline{\mathrm{OA}}, \overline{\mathrm{OB}}$ and $\overline{\mathrm{OC}}$.