Online Geometry theorems, problems, solutions, and related topics.
Geometry ProblemLevel: Mathematics Education, High School, Honors Geometry, College.Click the figure below to see the complete problem 699.
http://img821.imageshack.us/img821/6871/problem699.pngBD cut EF at G ( see picture)Note that DG=OG (angle ABC=60)Triangle ABG similar to tri. EDG with ratio =BG/DG=3So x= AB/3= 4Peter Tran
DAC = 30, AED = 120 imply ADE = 30So AE = ED = xFC = DF = x (by symmetry)So x = AE = EF = FC = AC/3 = 4