William Chapple (surveyor)
From Wikipedia, the free encyclopedia
William Chapple (1718–1781) was an English surveyor and mathematician. His mathematical discoveries were mostly in plane geometry and include:
- the first proof of the existence of the orthocentre of a triangle,
- a formula for the distance between the incentre and circumcentre of a triangle,
- the discovery of Poncelet's porism on triangles with a common incircle and circumcircle.
He was also one of the earliest mathematicians to calculate the values of annuities.