class C and B comms on sectionals?

In the legend on sectional charts there are a number of frequencies
listed for the various class B and C airspaces and airports.

For example, the northern florida chart has jacksonville listed as
"120.75 (091-180)". Now, during my commercial checkride a month ago my
examiner asked me what the numbers in parenthesis were and I said they
were courses from that C-airspace primary airport. So if you would draw
lines from Jacksonville international and out on a magnetic course of
091 and 180 degrees, you would have as a result a pie-shaped sector on
the chart. If you're approaching the C-airspace and your location is
withing that pie-sector you should use 120.75 Mhz to get your clearance
to enter the airspace.

There is also a small COMMs box on the chart itself located southeast
of the airspace so that makes sense to me.

However, my examiner said that 091-180 in the legend are in fact
RADIALS. The airspace in question on my checkride was the B airspace
around orlando, and she said these numbers are radials from (in that
case) ORL VOR and not courses from the airport.

1. Why would they use VOR radials for this on a VFR chart, when a VOR
isn't even required for VFR flight?

2. The C airspace set up for Jacksonville international doesn't even
have a VOR.


Is there a source where I can get more information on the legend that
the sectionals have?