Answer:
Step-by-step explanation:
I would check my math but 4/3 = 1.3 x 18= 24 divided by 2 for radius would be 12x12=144 x pie or 3.14 would be 452.16
dot on top of earth = plane position at the time of observation (right one when 37°, left one 53°)
then the geometry is zoomed on the left side
Slot method
20 options
3 slots
First slot: 20 options
Second slot: 19 options (one used up for 1st slot)
Third slot: 18 (one less than last)
Multiply them
20 times 19 times 18=6840
Answer is 6840 ways