How to connect four buildings into one LAN?

Question

Computer networks

I am doing coursework. I did not find an answer to my question on the Internet.
It is necessary to combine 4 buildings into one LAN. Building 1 is 1 km away from building 2, building 2 is 200 m away from building 3, building 4 is 10 km away from building 3. There is also an Internet provider at a distance of 5 km. Cable ducts cannot be laid between buildings. And you need a data transfer rate over the Internet of 50 Mbps.
Conducted a network in buildings. I just don't know how to connect buildings with a great distance. You can use Wi-Fi between buildings 2 and 3, but I don’t know what to do with other buildings. Perhaps satellite Internet, Wi-Fi is unlikely to be able to transmit for 10 km.

Answer 1

посмотрите решения от ubiquiti у них есть решения до 15км

Answer 2

Something like www.router-switch-shop.eu/2x-outdoor-wireless-brid...
More options and information can be googled for "wireless 10km".