A circular arc whose radius is 4 cm makes an angle 45° at the centre. Find the perimeter of the sector formed.

(Take π = $\frac{22}{7}$)

Angle subtended by the largest chord of the circle to a point on the same circle measures:

The distance between the centres of two circles having radii 22 cm and 18 cm, is 32 cm. The length (in cm) of the direct common tangent of the two circles is:

In the following figure, O is the centre of the circle. Its two chords AB and CD intersect each other at point P inside the circle. If AB = 18 cm, PB = 6 cm and CP = 4 cm, then find the measure of PD.