Definition of Diameter

  • Diameter is a line segment that passes through the center of a circle with both its endpoints lying on the circle.


Examples of Diameter

  • In the circle shown, the line segments AB and PQ are the  diameters of the circle. Notice that they have their endpoints on the circle and pass through the center O of the circle.


More about Diameter

  • A diameter is the longest chord of a circle.
  • A diameter is double the radius of a circle.

Solved Example on Diameter

Sunny bought a circular ring of diameter 32 cm. Find the radius of the ring.


A. 64 cm

B. 32 cm

C. 16 cm

D. 8 cm

Correct Answer: C


Step 1: Diameter of a circle = 2 × radius.

Step 2: Therefore, radius =.


Related Terms for Diameter

  • Circle
  • Chord
  • Endpoint
  • Line Segment


Additional Links for Diameter