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1962 AMC 12 Question 7

AMC12 · 1962 AMC 12

Question 7

Let the bisectors of the exterior angles at $B$ and $C$ of triangle $ABC$ meet at $D.$ Then, if all measurements are in degrees, angle $BDC$ equals:
  1. $\dfrac12(90-A)$
  2. $90-A$
  3. $\dfrac12(180-A)$
  4. $180-A$
  5. $180-2A$