Re: [中學] 幾何題

[suhorng ( )]

     A
      ----
     |    |
D    |    |
 ---- ---- ---- B
|    |    |    |
|    |    |    |
 ---- ---- ----
C
     __  __  __
連接 AB, BC, CA 形成直角三角形

∠3 = ∠CBD
∠2 = ∠ABD

所以角1 = π/4

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→ suhorng     :所以相加為π/2