返回题库

PUMaC 2013 · 几何（B 组） · 第 2 题

PUMaC 2013 — Geometry (Division B) — Problem 2

专题
Discrete Math / 离散数学
难度
L3
来源
PUMaC

题目详情

  1. [ 3 ] Triangle ABC satisfies ∠ ABC = ∠ ACB = 78 . Points D and E lie on AB, AC and satisfy ◦ ◦ ◦ ∠ BCD = 24 and ∠ CBE = 51 . If ∠ BED = x , find x .
解析
  1. [ 3 ] Triangle ABC satisfies \ ABC = \ ACB = 78 . Points D and E lie on AB, AC and satisfy \ BCD = 24 and \ CBE = 51 . If \ BED = x , find x . Solution Immediately observe BCD and BCE are isosceles. Therefore CB = CD = CE : \ BCD then \ BED = = 12 . 2