文 [1]给出了三角形外角平分线构成的三角形的两个性质 ,本文再给出几个 .定理　如图 1,△DEF是△ABC三条外角平分线构成的三角形 ,设△ABC和△DEF的面积分别为△和△′,外接圆和内切圆半径分别为R、R′,r ,r′ ,则图 1R′ =2R (1)△′△ =2Rr (2 )r′≥ 2r (3)证明　记BC=a ,C The paper [1] gives two properties of the triangle formed by the bisector of the triangle outer angle. This paper gives several theorems. Theorem Figure 1. △DEF is the triangle formed by the three external bisectors of △ABC. Let △ABC and △DEF be The areas are △ and △ ′ respectively, and the radius of the circumcircle and the inscribed circle are R, R′, r, and r′, respectively. Then, 1R′ = 2R (1) Δ′Δ = 2Rr (2) r′ ≥ 2r ( 3) Proof record BC=a ,C