How much metal ramp material will be needed to cover the surface all six ramps, after framing is in place?

Question

The hexagons need to be ADA (Americans with Disabilities Act) compliant. Contractors need to install a ramp for each external hexagon. To meet ADA requirements, the slope of each ramp must be 1:12. Doors are 12” off the ground. Ramps will be 12’ long. How much metal ramp material will be needed to cover the surface all six ramps, after framing is in place?

Answer 1

If the door is one foot off the floor, then the entire ramp would be 12' to comply with the slope of 1/12.

One ramp is 12'. From where did the "surface of six ramps" come?