Swing an arc from C with the divider set to C'
Divide on side of the base of the arc into five equal divisions
On the same side divide the arc into five divisions
Connect each corresponding marker
Create five equal divisions between AC and CB; erect a perpendicular at each point
Transfer the length of the four segments in the arc to the corresponding four perpendiculars on the baseline between A and C; repeat for the perpendiculars between C and B using the same heights
Using a batten draw a curve through each of the intersections to complete the expansion