Answer:
The area of shaded region is 226.4 meter squared.
Step-by-step explanation:
Radius of the circle = r =18.6 m
Angle subtended by chord
Area of sector = 
In ΔOAB
∠A+∠B+∠O= 180°
2∠A+123°= 180°(∠A=∠B, isosceles triangle)
∠A=∠B=28.5°
AC=BC (Radius of the circle bisects the chord at right angle.)...(1)
In ΔOAC

OC = 8.87 m

AC = 16.34 m
AB = AC+AB=16.34 m+16.34 m=32.68 m (from (1))
Area of the ΔOAB = 
=
Area of segment = Area of sector - Area of triangle:

The area of shaded region is 226.4 meter squared.