回復 22# leo790124 的帖子
用孟氏定理可算出
AR:DR = EP:BP = CQ:FQ = 2:3
△AFR:△ABD = (1 * 2):(4 * 5) = 1:10
△AFR:△ABC = 1:20
△BDP:△BCE = (1 * 3):(2 * 5) = 3:10
△BDP:△ABC = 1:10
△CEQ:△ACF = (1 * 2):(3 * 5) = 2:15
△CEQ:△ABC = 1:30
△PQR = △ABC - (△ABD + △BCE + △ACF) + (△AFR + △BDP + △CEQ)
△PQR:△ABC = 1:10