Triangle \(ABC\) is the boundary of a nature reserve.
\(A\), \(B\) and \(C\) are three points on level ground.
\(AB=7\) km.
\(C\) is \(12\) km due east of \(A\).
The area of the nature reserve is \(33\text{ km}^2\).
Show that angle \(BAC=51.8^\circ\).[3]
Calculate the length of \(BC\).[2]
the bearing of \(B\) from \(C\).[3]
An observation deck is \(60\) m above point \(B\).
A path is to be built from \(B\) to a point on \(AC\), across the nature reserve. Find the shortest possible length of the path.[2]
A visitor is at the top of the observation tower. Find the greatest angle of depression from the top of the tower to a point on \(AC\).[2]