How to make a Humanoid move to a certain position but x amount of studs away from that position?

Pythagorean Identity

basically, the pythagorean identity establishes that:

sin^2(?) + cos^2(?) = 1 (? being the angle measure / radians)

Which, if you, on a graphic calculator like desmos, were to graph

r = sin^2(?) + cos^2(?) (r standing for radius)

you would end up with a circle with radius 1

With that said, you could manipulate it so that you end up with a circle of any radius, for example, if you wanted a circle with radius a or radius 5, you could do:

r = asin^2(?) + acos^2(?)

r = 5sin^2(?) + 5cos^2(?)

Making the Code

local sPos = Vector3.new(1,0,2)--starting position

local function stud (theta)
	local pos = Vector3.new(5*math.sin(theta),0, 5*math.cos(theta))
		local finPos = sPos + pos

print((finPos - sPos).magnitude,"::",pos,"::",finPos,"::",math.deg(theta))
end

for i = 1, 360 do
	stud(math.rad(i))
end

Or more simplfied:

local humanoid = --humanoid object of your choice
local theta = math.rad(69)--for the memes
local sPos = Vector3.new(1,0,2)--some starting position
local pos = Vector3.new(5*math.sin(theta),0,5*math.cos(theta))
local finPos = sPos + pos --finished position

print((finPos - sPos).magnitude)--check distance
humanoid:MoveTo(finPos)

Note that I did not do 5*math.sin(theta)^2 or 5*math.cos(theta) in that script

explanation

This is probably the part of the answer I'm going to be lambasted for due to incorrect terminology,so i recommend skipping this part, if you already know the math behind it. But nevertheless, I digress. Put simply, this works, because, essentially, and point on a circle is reachable with a right triangle.

For a certain angle measure ?, the hypotenuse is the radius of the circle(r), as it reaches from the center to the edge of the circle. the vertical side would be r* sin(?) and the horizontal side would be r*cos(?).

This, on a circle with radius 1 would mean that the hypotenuse is 1, the vertical side is sin(?) and the horizontal side is cos(?), using pythagorean theorem gives us the famous equation of

sin^2(?) + cos^2(?) = 1

Useful Links

Here is the part of the answer where you see people explain the concept far better than i did

MathBits

Khan Academy

Hopefully this helped!