Network inventory
You're documenting the LAN. Use each PC's own commands (not the IP settings dialog) to find its details, and fix the one PC that can't leave the LAN: the gateway is the router, 10.1.1.1.
How it works: this is VulnTech NetLab, a network simulator running in your browser. Click a device in the diagram to open its console and type commands, just like on real equipment (? shows help, Tab finishes a word). Click a cable to inspect it. Tasks tick themselves off as you complete them; questions are answered in the box under each task. Your work is kept if you reload; Reset starts the network over.
Solution explanation
ipconfig /all shows the MAC as the Physical Address. PC2's ip addr shows 10.1.1.12/25: a /25 mask (255.255.255.128). That still includes .1, .11 and .13, so it works here, but it doesn't match the /24 the others use and is worth reporting. PC3's routing table had no default line, so it could talk only inside 10.1.1.0/24; sudo route add default 10.1.1.1 fixes it.
Show solution
[PC1]
ipconfig /all
[PC2]
ip addr
[PC3]
netstat -rn
sudo route add default 10.1.1.1
ping -c 3 10.9.9.10