The diagram shows a semicircle, centre \(O\), radius 16 cm.
Show that angle \(AOB=1.287\) radians, correct to 3 decimal places.[2]
Calculate the area of the shaded region.[3]
The semicircle is the cross section of a water trough of length 2.8 m, lying on level ground. The shaded area represents the water in the trough.
Calculate the volume of water, in \(\text{cm}^3\), in the trough.[2]
Calculate the number of litres of water that must be added to fill the trough.[3]