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.
Daniel Hale Williams - Introduction: African American Doctor Daniel Hale Williams is credited with having performed open heart surgery on July 9, 1893 before such surgeries were established. In 1913, Daniel Hale Williams Williams was the only African American member of the American College of Surgeons.Dr. Daniel Hale Williams in 1893?