In a triangle , ,

MATHEMATICS · Single correct · AoPS · Mathematics · Graphing Quadratics · Graphing Quadratics

Problem

In a triangle

ABC

AD

BE

, and

CF

are the altitudes, and

R

is the circumradius. The radius of the circle through

D

E

, and

F

is: (1)

2R

(2)

R

(3)

\frac{R}{2}

(4) None of these