MathDB
integer lenght of angle bisector 2020 MBMT p42

Source:

February 13, 2022
geometryangle bisectorMBMT

Problem Statement

ABC\vartriangle ABC has side lengths AB=4AB = 4 and AC=9AC = 9. Angle bisector ADAD bisects angle AA and intersects BCBC at DD. Let kk be the ratio BDAB\frac{BD}{AB} . Given that the length ADAD is an integer, find the sum of all possible k2k^2 .