A chord of length cm lies cm from the centre of a circle. Find the radius in cm.

Answer and explanation

Correct answer: B. 13

  1. Step 1: The perpendicular from the centre bisects the chord, giving a right-angled triangle with sides and .
  2. Step 2: cm.
Answer
13.
Why not the others: 17: it adds the half-chord and the distance. 5: that is half the chord. 12: that is the distance to the centre.

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