Multiple choice

In a circle, a ten cm long chord is at a distance of 12 cm from the centre of the circle. Length of the diameter of the circle (in cm) is:

  1. 20

  2. 22

  3. 13

  4. 26

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Use the chord-radius relationship: half the chord (5 cm), distance from center (12 cm), and radius form a right triangle. By Pythagorean theorem: r² = 5² + 12² = 25 + 144 = 169, so r = 13 cm. The diameter is 2r = 26 cm.