I have recently gotten fire giants for a slayer task and have never killed them before. Where is the best place to kill them with melee and with ranged?

Best place is the Waterfall from the Waterfall quest. You can range them there and stay for your whole task.

Melee would probably be the Brimhaven dungeon (after 20 mins dogs will leave you alone) and ranged would be the waterfall dungeon.

Okay, thanks for the replies.

brimhaven dungeon is best, waterfall is way too crowded. If you want to range there are range spots for the fire giants in brimhaven dungeon the upstairs ones.