MathDB
2013 HMMT Guts #14: Angle Bisectors Galore

Source:

March 26, 2013
HMMTtrigonometryratiogeometryangle bisector

Problem Statement

Consider triangle ABCABC with A=2B\angle A=2\angle B. The angle bisectors from AA and CC intersect at DD, and the angle bisector from CC intersects AB\overline{AB} at EE. If DEDC=13\dfrac{DE}{DC}=\dfrac13, compute ABAC\dfrac{AB}{AC}.