3.29: Chord with an arc from an external centre on the circle

In this question the units are metres.
The diagram shows a circle, centre and radius .
The chord has length .
The point lies on the circle such that .
The arc is part of a circle, centre .
(a)[2]
Find the exact value of angle in radians.
(b)[6]
Hence find the area of the shaded region. Give your answer in terms of .
