The Angle Bisector Theorem gives information about ratios of side length in a triangle when an angle bisector is drawn. [url=https://en.wikipedia.org/wiki/Angle_bisector_theorem]https://en.wikipedia.org/wiki/Angle_bisector_theorem[/url] gives the theorem. A question like this appeared in 1966, [url=http://artofproblemsolving.com/wiki/index.php?title=1966_AHSME_Problems/Problem_11]http://artofproblemsolving.com/wiki/index.php?title=1966_AHSME_Problems/Problem_11[/url]