TrigInTriangle LawOfSines LawOfCosines PlaneGeometry Difficult

Problem - 3139

In $\triangle{ABC}$, $AE$ and $AF$ trisects $\angle{A}$, $BF$ and $BD$ trisects $\angle{B}$, $CD$ and $CE$ trisects $\angle{C}$. Show that $\triangle{DEF}$ is equilateral.


The solution for this problem is available for $0.99. You can also purchase a pass for all available solutions for $99.

report an error