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 that both of them 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