The cables that are included have such funny plugs at the end and come directly from the speakers to extend them you would have to tinker a bit. I think the cables that are included have a length of about 6 to 8 metres. My question is why do you want to place the speakers so far away from the subwoofer? Not that much comes out of the small speakers and if they are installed too far away, you will hardly hear them in my opinion.

Additional cables if the ones supplied are not long enough:
Available in different lengths

Velleman PLW215 Loudspeaker cable 2x1.5mm² (100m, Transparent, Copper, 1.50mm²)

Yes, the extension cables are included.