Midpoint of a pyramid

Hi everyone,

Can anyone tell me how I can find the center of a triangular pyramid given its 4 vertices in 3d space “If you don’t know that it is a pyramid” (i.e. you can’t take the top point and divide it by 2 to get the y value etc.) My 3D Math skills did not suffice :frowning:

Thanks,

P.S: Not homework.