(i)[2]
State how far the centre of mass of the lamina is from $AB$ and from $BC$.
(ii)[2]
The lamina is suspended freely at $B$ and is in equilibrium. Find the angle made by $AB$ with the horizontal.
(iii)[3]
A force with magnitude $12\\,\\text{N}$ acts along the edge $AC$ of the lamina, from $A$ towards $C$. The lamina, still supported at $B$, is now in equilibrium with $AB$ vertical. Calculate the weight of the lamina.