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1979 AMC 12 Question 12

AMC12 · 1979 AMC 12

Question 12

In the adjoining figure, $CD$ is the diameter of a semicircle with center $O.$ Point $A$ lies on the extension of $DC$ past $C;$ point $E$ lies on the semicircle, and $B$ is the point of intersection (distinct from $E$) of line segment $AE$ with the semicircle. If length $AB$ equals length $OD,$ and the measure of $\angle EOD$ is $45^\circ,$ then the measure of $\angle BAO$ is

Question illustration
  1. $10^\circ$
  2. $15^\circ$
  3. $20^\circ$
  4. $25^\circ$
  5. $30^\circ$