nine-point circle

English

Acute triangle ABC, with its nine-point circle

Alternative forms

• nine points circle

Etymology

So called because the circle passes through nine points of interest: the feet of the three altitudes, the centers of the three sides, and the midpoints of the segments which join the triangle's vertices with its orthocenter.

Noun

nine-point circle (plural nine-point circles)

1. (geometry) That circle which passes through the feet of the altitudes of a given triangle.

Further reading

• nine-point circle on Wikipedia.Wikipedia