How to Calculate 3D Fillet Tangent Points and Center in Excel?

[yoman]

Homework Statement

I have 3 known point, with coordinate P1-(X1, Y1, Z1), P2-(X2, Y2, Z2), P3-(X3, Y3, Z3).

straight line is draw from P1 to P2, P2 to P3. they are "not" collinear.

I would like to fit a round fillet to the conner with a "Known" radius of R, and I would like to know the coordinate of the 2 tangent point and the center of the fillet circle.

How can I calculated it in 3D coordinate with a sample single equation for each of the tangent point and center of the fillet, so I can use in Excel. Is this possible?

Please help as I need to complet this for my project.

Homework Equations

The Attempt at a Solution

 

[Gokul43201]

Is this a math project or a machining project?

Can you write down the equations of the 2 lines? From the equations, can you find the angle between them? Does noticing that the center of the circle lies on the angle bisector help (there's a right triangle of known angles that can be drawn)?