(a(i))[1]
Explain why the value of $\angle BCA$ is $56^{\circ}$.
(a(ii))[2]
Find the value of $\angle COD$.
(a(iii))[1]
Find the value of $\angle OCE$.
(b(i))[2]
Explain why $PT$ is equal to $PR$.
(b(ii))[3]
This figure is a section of the larger diagram above. $PQ = 12\text{ cm}$, $PR = 5\text{ cm}$ and $QR = 8.5\text{ cm}$. It is given that $\frac{PQ}{PR} = \frac{QS}{SR}$. Find $SR$.