Multiple choice

If the length of a chord $AB$ is equal to the radius $OA$ of the circle, then $\angle ABO $ equals ($O$ is the center)

  1. $120$
  2. $60$
  3. $45$
  4. $30$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

If chord AB equals radius OA, then triangle OAB is equilateral. Thus, all angles in triangle OAB are 60 degrees. Therefore, angle ABO is 60 degrees.

AI explanation

Since the length of chord AB equals the radius OA, and OB is also a radius, all three sides of triangle OAB are equal. This means triangle OAB is an equilateral triangle. In an equilateral triangle, all interior angles are 60 degrees, so the angle ABO is 60 degrees.

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