👉 Poncelet's Theorem, also known as Poncelet's U, is a fundamental result in mathematics that describes how the volume of a solid can be expressed using only integer multiples of its edges. It was proved by Swiss mathematician and physicist Adrien-Marie Legendre in 1805. In this theorem, poncelet's principle states that for any finite number of parallel planes (edges) through a solid, the volume of the solid cannot exceed the sum of these