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Mathematics vocabulary · Geometry

Diameter

Meaning in mathematics, with examples

/daɪˈæmɪtər/nounCore term

In mathematics, diameter means: A straight line from one side of a circle or sphere to the other through its centre, or the length of this line, which is twice the radius.

In Turkish: çap

How it is used

Often given in real-life problems about pipes, wheels and pizzas, so you have to halve it to get the radius. The circumference of a circle is π times the diameter (πd).

Example sentences

  1. The wheel has a diameter of 70 cm, so its radius is 35 cm.

  2. Be careful: the question gives the diameter, not the radius.

Common collocations

  • diameter of a circle
  • in diameter
  • a diameter of
  • diameter and radius
  • radiusThe distance from the centre of a circle or sphere to any point on its edge; it is half the diameter.
  • perimeterThe total length of the boundary of a flat shape; for a rectangle 5 cm long and 3 cm wide, the perimeter is 16 cm.
  • areaThe size of a flat surface, measured in square units such as cm² or m²; a rectangle 4 m long and 3 m wide has an area of 12 m².
  • volumeThe amount of space a solid object takes up or a container holds, measured in cubic units such as cm³ or m³.

More terms: Geometry

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