Raider Flare Distance?

When you see a Raider flare in the air, is there an easy way to judge how far that downed Raider is from me?

For example, I ping the flare at the height of its trajectory and it says 400 meters. How far away (ball park) is the down Raider?

And I’m sure there is basic math to adjust the distance to the flare from my position to where the flare originated, but I don’t know it? Is there a rule of thumb I can go by?