How would I have something fire when a part is in the region of 90 degree angle in front of a part? I think I have to do something with math.rad, math.deg, magnitude, and Region3. Here is a (fairly messy) picture of describing what i want to happen:
https://gyazo.com/f0182173181dcda7c2c22b95c89045eb
Here is what im doing right now (although im sure it is completely wrong)
local Distance = 50
local Equation = math.rad(50 / 90)
local playerDistance = plr.Character.HumanoidRootPart.Position
if (playerDistance - script.Parent.HumanoidRootPart.Position).magnitude <= Equation then
--do stuff
else
--do more stuff
end

4 comments
I'd probably just have a cylinder/sphere with .Touched event listening if it's the Player's Character that comes to exist in proximity over time.
If it's the area that comes to exist at a point in time then I'd probably Region3 at that time and then use the distance (radius) from the centre of the Region to determine true existence.
Get the script to run a checkup on the HumanoidRootPart's orientation of the player, then just proceed.
How would I do that?