Carnot's theorem

Meanings

1. A theorem for the maximum efficiency obtainable from a heat engine.
2. A theorem stating that the sum of the signed distances from the circumcenter D to the sides of an arbitrary triangle ABC is DF + DG + DH = R + r, where r is the inradius and R the circumradius of the triangle.
3. A theorem describing a relation between conic sections and triangles.
4. A theorem describing a necessary and sufficient condition for three lines that are perpendicular to the (extended) sides of a triangle having a common point of intersection.