triangle problem

coderfreak2022

For a triangle with vertices A, B and C, determine if a vertex X lies on the plane defined by the three vertices of triangle.

Here I assume that since vertex X lies on plane, find coordinates and perpendicular distance from point, then check if vertex X lies. What is the equation here?

coderfreak2022

My approach is to check to see if the vertex lies in the plane of the triangle. Then project the triangle and vertex into 2D.

Any suggestions?