Lietadielko Aeroplane (HKCEE 1999 )

In the figure, ABC is an equilateral triangle of side 24 cm and BD = DE = EF = FC. It is folded to form an aeroplane by dragging the red point so that D and F coincide. The aeroplane is supported by two vertical sticks BM and CN so that A,B, D, F, C lie on the same plane. (a) Find the distance between the tips, B and C, of the wings of the aeroplane. (b) Find the inclination of the wings of the aeroplane to the horizontal ground. (c) Find the length of the stick CN.

Information: Lietadielko Aeroplane (HKCEE 1999 )