Solid with eight equilateral triangles

A certain solid was made as shown Fig.1 of eight equilateral triangles. Also as shown in Fig. 1, the point in the middle of each side of this solid was connected by the straight line and this solid was developed as shown in Fig. 2.

Draw the remaining straight lines drawn on the solid on the development view of Fig. 2.

AB of Fig. 2 is the same as AB of Fig. 1.

Answer