THE BODY PERCENTAGE: the body is broken up into percentages of surface area taken up by each part for both ADULT FRONT/BACK and CHILD. Also, just notice how differently proportioned the child is comparing his/her percentages to the identical ones on the adult. This is mainly used for judging burns' severity when covering areas.
Image result for how we calculate the area with total station
Einstein's equation, for calculating the geometry of spacetime.