That is an important theorem in geometry: if two lines intersect to form adjacent congruent angles, then the lines are perpendicular. Those congruent angles would be right angâ¦les.
Williams later became chief surgeon of the Freedmenâs Hospital. Daniel Hale Williams III was born on January 18, 1856, in Hollidaysburg, Pennsylvania, to Sarah Price Williams and Daniel Hale Williams II. The couple had several children, with the elder Daniel H. Williams inheriting a barber business.
Wednesday 26 January 2011 13.58 EST First published on Wednesday 26 January 2011 13.58 EST. Daniel Bell, who has died aged 91, was a widely influential social observer and emeritus professor of social sciences at Harvard University, where he had taught since 1969.