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.
The Daniel Hale Williams House is the former home of Dr. Daniel Hale Williams (1856-1931), one of the first major African American surgeons. Located at 445 East 42nd Street in Grand Boulevard community area of Chicago Illinois, the building was designated a National Historic Landmark in 1975.