(a) If \(\frac{3p + 4q}{3p - 4q} = 2\), find \(p : q\).

(b) The diagram shows the cross section of a bridge with a semi-circular hollow in the middle. If the perimeter of the cross section is 34 cm, calculate the :

(i) length PQ; (ii) area of the cross section. 

[Take \(\pi = \frac{22}{7}\)].