This video explains the center of gravity in general. When is the center of gravity of a structure equal to the geometric center of gravity, and what are centroidal axes? This tutorial deals with these questions.
Afterwards, the calculation is carried out using an example known in civil engineering.
This is the component cross-section of a slab and concrete beam. Both have the same density; therefore, it is possible to determine the center of gravity.
Since the usual explanation (using tables) of centroidal distances and partial surfaces is confusing, it has been omitted, and the topic is clearly explained using colors.